oversight

Truck Underride Guards: Improved Data Collection, Inspections, and Research Needed

Published by the Government Accountability Office on 2019-04-15.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

             United States Government Accountability Office
             Report to Congressional Requesters




             TRUCK UNDERRIDE
March 2019




             GUARDS

             Improved Data
             Collection,
             Inspections, and
             Research Needed




GAO-19-264
                                             March 2019

                                             TRUCK UNDERRIDE GUARDS
                                             Improved Data Collection, Inspections, and Research
                                             Needed
Highlights of GAO-19-264, a report to
congressional requesters




Why GAO Did This Study                       What GAO Found
Truck underride crashes are collisions       According to crash data collected by police and reported by the Department of
in which a car slides under the body of      Transportation’s (DOT) National Highway Traffic Safety Administration (NHTSA),
a truck—such as a tractor-trailer or         fatalities from “underride” crashes, such as those pictured below, represent a
single-unit truck—due to the height          small percentage of all traffic fatalities.
difference between the vehicles.
During these crashes, the trailer or         Crash Tests of Rear Guards with (left) and without (right) Passenger Compartment Intrusion
truck may intrude into the passenger
compartment, leading to severe
injuries or fatalities. Current federal
regulations require trailers to have rear
guards that can withstand the force of
a crash, whereas the rear guards
required for single-unit trucks do not
have to be designed to withstand a
crash. There are no federal side or
front underride guard requirements.
                                             From 2008 through 2017, an average of about 219 fatalities from underride
GAO was asked to review data on              crashes involving large trucks were reported annually, representing less than 1
truck underride crashes and                  percent of total traffic fatalities over that time frame. However, these fatalities are
information on underride guards. This        likely underreported due to variability in state and local data collection. For
report examines (1) the data DOT             example, police officers responding to a crash do not use a standard definition of
reports on underride crashes and (2)         an underride crash and states’ crash report forms vary, with some not including a
the development and use of underride         field for collecting underride data. Further, police officers receive limited
guard technologies in the U.S. GAO
                                             information on how to identify and record underride crashes. As a result, NHTSA
analyzed DOT’s underride crash data
                                             may not have accurate data to support efforts to reduce traffic fatalities.
for 2008 through 2017; reviewed
NHTSA’s proposed regulations and             Underride guards are in varying stages of development, and gaps exist in
research on new guard technologies;          inspection of rear guards in current use and in research efforts for side guards.
and interviewed stakeholders,
including DOT officials, industry and        •   NHTSA has proposed strengthening rear guard requirements for trailers (the
safety groups, and state officials               rear unit of a tractor-trailer) and estimates about 95 percent of all newly
selected based on reported underride             manufactured trailers already meet the stronger requirements. Although
crash fatalities and other factors.              tractor-trailers are inspected, Federal Motor Carrier Safety Administration
                                                 annual inspection regulations do not require the rear guard to be inspected,
What GAO Recommends                              so damaged guards that could fail in a crash may be on the roadways.
GAO recommends that DOT take                 •   Side underride guards are being developed, but stakeholders GAO
steps to provide a standardized                  interviewed identified challenges to their use, such as the stress on trailer
definition of underride crashes and              frames due to the additional weight. NHTSA has not determined the
data fields, share information with              effectiveness and cost of these guards, but manufacturers told GAO they are
police departments on identifying                unlikely to move forward with development without such research.
underride crashes, establish annual          •   Based on a 2009 crash investigation, the National Transportation Safety
inspection requirements for rear                 Board (NTSB) recommended that NHTSA require front guards on tractors.
guards, and conduct additional                   NHTSA officials stated that the agency plans to complete research to
research on side underride guards.               respond to this recommendation in 2019. However, stakeholders generally
DOT concurred with GAO's                         stated that the bumper and lower frame of tractors typically used in the U.S.
recommendations.                                 may mitigate the need for front guards for underride purposes.
View GAO-19-264. For more information,       •   Regarding single-unit trucks, such as dump trucks, NTSB has recommended
contact Susan Fleming at (202) 512-2834 or       that NHTSA develop standards for underride guards for these trucks, but the
FlemingS@gao.gov.
                                                 agency has concluded these standards would not be cost-effective.
                                                                                          United States Government Accountability Office
Contents


Letter                                                                                     1
               Background                                                                  4
               Underride Crash Fatalities Reported by NHTSA Data Are
                 Relatively Low but Are Likely Undercounted                              10
               Underride Guards Are in Varying Stages of Development, and
                 Gaps Exist in Inspection and Research                                   18
               Conclusions                                                               32
               Recommendations for Executive Action                                      33
               Agency Comments                                                           33

Appendix I     Objectives, Scope, and Methodology                                        35



Appendix II    Comments from the Department of Transportation                            40



Appendix III   GAO Contact and Staff Acknowledgments                                     41


Tables
               Table 1: Commercial Vehicle Inspection Types                                9
               Table 2: Reported Underride Crash Fatalities, Total Traffic
                       Fatalities, and Large Truck Fatalities, 2008 through 2017         11

Figures
               Figure 1: Crash Tests of Rear Guards with (left) and without (right)
                        Passenger Compartment Intrusion                                    5
               Figure 2: Overview of a Tractor-Trailer and Examples of Rear and
                        Side Underride Guards                                              6
               Figure 3: Side Guard Examples                                               8
               Figure 4: Insurance Institute for Highway Safety Rear Guard
                        Testing Procedure at Full Width, 50 Percent Overlap, and
                        30 Percent Overlap                                               21
               Figure 5: Example of a Damaged Rear Guard                                 22
               Figure 6: Examples of a Conventional Tractor (left) and Cab-Over
                        Tractor (right)                                                  27




               Page i                                       GAO-19-264 Truck Underride Guards
Abbreviations

ANPRM             advance notice of proposed rulemaking
CVSA              Commercial Vehicle Safety Alliance
DOT               Department of Transportation
FARS              Fatality Analysis Reporting System
FMCSA             Federal Motor Carrier Safety Administration
IIHS              Insurance Institute for Highway Safety
MMUCC             Model Minimum Uniform Crash Criteria
NHTSA             National Highway Traffic Safety Administration
NPRM              notice of proposed rulemaking
NTSB              National Transportation Safety Board



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Page ii                                                GAO-19-264 Truck Underride Guards
                       Letter




441 G St. N.W.
Washington, DC 20548




                       March 14, 2019

                       The Honorable Roger Wicker
                       Chairman
                       Committee on Commerce, Science, and Transportation
                       United States Senate

                       The Honorable Richard Burr
                       United States Senate

                       The Honorable Kirsten Gillibrand
                       United States Senate

                       The Honorable Marco Rubio
                       United States Senate

                       The Honorable John Thune
                       United States Senate

                       An “underride” crash occurs when a passenger vehicle slides under the
                       body of a tractor-trailer or “single-unit truck,” such as a delivery or dump
                       truck. 1 Due to the height difference between the vehicles, the car’s safety
                       features are bypassed because the point of impact is not the front bumper
                       of the car. Without these safety features to absorb the force of the
                       collision, the passenger compartment can be crushed when it contacts
                       the truck, potentially resulting in death or severe head and neck injuries
                       for the occupants. To help prevent or mitigate these crashes, federal
                       regulations require that the rear end of the trailer have a guard meeting
                       specific crashworthiness standards. With these guards in place, the front
                       of the car will impact the guard instead of sliding under the trailer and the
                       car’s safety features will engage to offer some protection to the car’s
                       occupants. Rear guards of specific dimensions are also required for
                       single-unit trucks, but these guards are not required to be able to
                       withstand the force of a crash. There are no federal requirements for side
                       or front underride guards on any type of large truck in the United States.
                       1
                        A tractor-trailer consists of a front unit, called a tractor, and a rear unit, called a trailer.
                       Single-unit truck types are differentiated by their weight and number of axles, and not on
                       their height from the ground.




                       Page 1                                                      GAO-19-264 Truck Underride Guards
However, legislation aimed at, among other things, requiring the use of
side and front underride guards on all large trucks was introduced in the
House of Representatives and the Senate in December 2017. 2 New
legislation regarding underride crashes was introduced in March 2019. 3

You asked us to review data on truck underride crashes and information
related to rear, side, and front underride guards in the United States. This
report examines: (1) the data the Department of Transportation (DOT)
reports on truck underride crashes and (2) the development and use of
truck underride guard technologies in the United States.

To address both objectives, we conducted a literature review to identify
studies regarding truck safety, in general, and underride guards, in
particular; we reviewed these studies and other documentation collected
from interviewees, as described below. We also interviewed a variety of
stakeholders familiar with topics related to underride crashes and guards,
including: officials from DOT’s National Highway Traffic Safety
Administration (NHTSA), as well as NHTSA’s data validation and training
contractor; the Federal Motor Carrier Safety Administration (FMCSA); the
National Transportation Safety Board (NTSB) and representatives from
the Insurance Institute for Highway Safety (IIHS). We interviewed seven
trailer manufacturers, nine trucking industry organizations, four
organizations representing tractor-trailer fleets, nine traffic safety groups,
and four organizations involved in transportation research. Additionally,
we interviewed officials of five state DOTs, five state police departments,
as well as two local police departments. 4 In selecting the states and
localities, we considered various factors—such as reported underride
crash fatalities and highway vehicle miles traveled—to identify states that
were similar in highway traffic trends and large truck-related fatality rates,
but that collected underride crash data differently. The results of these
interviews are not generalizable to all states and localities; however, they
offer examples of the types of experiences state DOTs and state and
local police have with underride crashes and inspections. We also

2
 H.R. 4622, Stop Underrides Act of 2017, 115th Cong. (2017). S. 2219, Stop Underrides
Act of 2017, 115th Cong. (2017).
3
 H.R. 1511, Stop Underrides Act of 2019, 116th Cong. (2019). S. 665, Stop Underrides
Act of 2019, 116th Cong. (2019).
4
  We interviewed state DOT and state police officials from the following states: California,
Illinois, Indiana, Pennsylvania, and Tennessee. We interviewed local police officials from
the following localities: Chicago, Illinois and Terre Haute, Indiana.




Page 2                                                  GAO-19-264 Truck Underride Guards
interviewed officials from transportation agencies in Canada and the
European Union.

For the first objective, we also analyzed DOT data on underride crashes
and fatalities from 2008 through 2017—the 10 most recent years for
which these data were available—and reviewed crash report forms from
all 50 states and the District of Columbia. We compared NHTSA’s data
collection efforts to federal internal control standards related to use of
quality information. 5 For the second objective, we reviewed NHTSA’s and
FMCSA’s regulations requiring rear guards, FMCSA’s regulations on
commercial vehicle inspections, DOT’s documentation on underride
guard technologies, and DOT’s data on commercial vehicle inspections.
To assess the reliability of DOT’s data on underride crashes and fatalities
and commercial vehicle inspections, we reviewed relevant documentation
and spoke with agency officials about the data’s quality control
procedures. We determined that the data were sufficiently reliable for the
purposes of this report, specifically to provide a high-level overview of
underride crashes and fatalities, as well as commercial vehicle
inspections within recent years. However, we did identify potential
underreporting of underride crashes and fatalities, as discussed in this
report. We compared DOT’s efforts to pertinent agency regulations on
commercial vehicle inspections, federal internal control standards related
to use of quality information, and a statement of federal principles on
regulatory planning and review. 6 See appendix I for a detailed description
of our objectives, scope, and methodology, including a list of
interviewees.

We conducted this performance audit from January 2018 to March 2019
in accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our
findings and conclusions based on our audit objectives. We believe that
the evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives.




5
 GAO, Standards for Internal Control in the Federal Government, GAO-14-704G
(Washington, D.C.: September 2014).
6
GAO-14-704G. Exec. Order No. 12866, 58 Fed. Reg. 51735 (Oct. 4, 1993).




Page 3                                             GAO-19-264 Truck Underride Guards
             An underride crash can occur during a collision between a passenger
Background   vehicle and a large truck—a tractor-trailer or a single-unit truck, such as a
             delivery or dump truck—if the height difference between the vehicles is
             sufficient to allow the smaller vehicle to slide under the body of the truck. 7
             The front and rear of passenger vehicles are designed to crumple in a
             crash and absorb the main force of an impact, while sensors detect the
             impact and activate safety features within the passenger compartment,
             such as air bags and seatbelt pretensioners. 8 However, the point of
             impact in an underride crash could be the hood of the passenger vehicle
             or—more severely—the windshield. Such impacts can result in
             “passenger compartment intrusion” by the large truck into the passenger
             area of the smaller vehicle. This intrusion can kill passengers or leave
             them with severe head and neck injuries. Underride guards on large
             trucks essentially lower the profile of the truck’s body to be more
             compatible with that of a passenger vehicle. An underride guard designed
             to withstand the force of a crash can prevent the car from sliding under
             the truck and provide an effective point of impact that will activate the
             car’s safety features to protect the car’s occupants. Figure 1 shows
             images from a video depicting the difference in underride crashes with
             and without passenger compartment intrusion on the rear of a tractor-
             trailer.




             7
              Of the approximately 11.5 million total registered large trucks in the U.S. in 2016, about
             2.8 million (24 percent) were tractor-trailers and about 8.8 million (76 percent) were single-
             unit trucks. FMCSA, 2018 Pocket Guide to Large Truck and Bus Statistics, (Washington,
             D.C.: August 2018).
             8
              Seatbelt pretensioners retract a limited amount of webbing to help minimize the forward
             movement of the occupant during a crash.




             Page 4                                                  GAO-19-264 Truck Underride Guards
Figure 1: Crash Tests of Rear Guards with (left) and without (right) Passenger Compartment Intrusion




                                         Note: The images shown are from a video about the difference between underride crashes with and
                                         without passenger compartment intrusion. To view the video, go to
                                         www.gao.gov/products/GAO-19-264.


                                         Rear and side underride guards limit a passenger vehicle’s ability to go
                                         under those areas of a trailer in a crash (see fig. 2). Front guards—
                                         currently used on tractors in some other countries, such as European
                                         Union countries—can reduce the likelihood that a truck would ride over a
                                         passenger vehicle in a crash, a situation sometimes referred to as
                                         “override”. In addition to saving lives and reducing serious injuries,
                                         improving traffic safety—including reducing underride crashes—may
                                         provide other benefits to society. Specifically, NHTSA has reported that
                                         preventing such crashes may result in savings in police and crash
                                         investigation resources and reduced property damage, among other
                                         things. Federal requirements, in regulations issued by NHTSA and
                                         FMCSA, exist for the installation of rear guards on most large trucks, but
                                         there are no federal requirements for side or front guards. 9




                                         9
                                          These federal requirements apply to trailers and single-unit trucks and exclude certain
                                         vehicles, including school buses. 49 C.F.R. §§ 571.223, 224, and 393.86.




                                         Page 5                                                    GAO-19-264 Truck Underride Guards
Figure 2: Overview of a Tractor-Trailer and Examples of Rear and Side Underride Guards




                                        NHTSA’s mission is to “save lives, prevent injuries and reduce economic
                                        costs due to road traffic crashes through education, research, safety
                                        standards and enforcement activity.” 10 As part of this mission, NHTSA
                                        requires that rear guards be installed on most trailers. Federal regulations
                                        requiring rear guards of specific dimensions date back to 1952, but the
                                        most current regulations—which set force and energy absorption
                                        standards, in addition to dimensional requirements—became effective in
                                        1998. 11 These crashworthy rear guards must be designed and tested to
                                        protect occupants in a crash of up to 30 miles per hour.

                                        In December 2015, NHTSA published a notice of proposed rulemaking
                                        (NPRM) that proposed to align U.S. regulations with stronger Canadian
                                        rear guard standards. 12 The Canadian standard includes a stronger

                                        10
                                          NHTSA, The Road Ahead: National Highway Traffic Safety Administration Strategic Plan
                                        2016-2020, DOT HS 812 343 (Washington, D.C.: October 2016).
                                        11
                                          49 C.F.R. §§ 571.223 and .224. These regulations require rear guards on trailers with a
                                        gross vehicle weight rating of 10,000 pounds or more.
                                        12
                                          80 Fed. Reg. 78418 (Dec. 16, 2015).




                                        Page 6                                                GAO-19-264 Truck Underride Guards
energy absorption requirement: 20,000 joules—a measurement of
energy—as compared to 5,650 joules in the U.S. NHTSA has not taken
action on this NPRM since it was proposed in December 2015. Single-
unit trucks that are more than 30 inches above the ground are required to
meet the dimensional specifications for rear guards set in 1952 but are
not required to meet any force or energy absorption standards. 13 NHTSA
introduced an advance notice of proposed rulemaking (ANPRM) in July
2015 that considered requiring rear guards with strength and energy
absorption criteria for all newly built single-unit trucks. However, NHTSA
has since withdrawn the ANPRM, stating that—based on the comments
received as well as analysis of the petitions—the changes being
considered were not justified.

Although there are no federal requirements for crashworthy side
underride guards, some crashworthy side guards are being developed.
For example, one aftermarket manufacturer has developed a side
underride guard that was crash-tested by IIHS and successfully
prevented underride crashes in tests at 35 and 40 miles per hour. Similar
looking technologies—including aerodynamic side skirts and
pedestrian/cyclist side guards—are installed on some trailers and single-
unit trucks, but they are not meant to mitigate underride crashes (see fig.
3).




13
  49 C.F.R. § 393.86. Unlike requirements for rear guards on trailers, these regulations
are not based on the truck’s weight.




Page 7                                                 GAO-19-264 Truck Underride Guards
Figure 3: Side Guard Examples




                                FMCSA’s primary mission is “to reduce crashes, injuries, and fatalities
                                involving large trucks and buses,” 14 and it does this, in part, through
                                developing safety regulations. These regulations include requirements for
                                rear guards for trailers consistent with Federal Motor Vehicle Safety
                                Standards and for single-unit trucks that are more than 30 inches above
                                the ground, as well as for multiple types of commercial vehicle
                                inspections that are performed by, for example, motor carriers and drivers
                                to ensure that commercial vehicles are safely operating. Table 1
                                describes the types of commercial vehicle inspections.




                                14
                                  FMCSA, Federal Motor Carrier Safety Administration Strategic Plan Fiscal Years 2015 –
                                2018, (Washington, D.C.: August 2016).




                                Page 8                                              GAO-19-264 Truck Underride Guards
Table 1: Commercial Vehicle Inspection Types

 Inspection Type                         Description
 Annual Inspection                       •  Required of all trucks, trailers, and buses. Employees of the motor carrier may conduct the annual
                                            inspections if the vehicles are not subject to a mandatory state inspection program.
                                         •  “Appendix G” of FMCSA’s regulations lists the equipment that must be inspected as part of the annual
                                            inspection.
 Roadside Inspection                     •  Inspectors—often certified state police officers—select commercial vehicles on the highway for
                                            roadside inspections.
                                         •  A standardized set of procedures is used to determine whether large trucks are operating safely.
                                            There are eight types of roadside inspections, with some inspections examining all parts of a
                                            vehicle—including the rear guard—and others reviewing a driver’s license and other administrative
                                            credentials.
 Pre-Trip Inspection                     •     Drivers are required to check that the vehicle is in safe and proper working condition.
 Driver Vehicle Inspection               •     Drivers are required to prepare a post-trip inspection report at the end of each operating day to
 Reports (“Post-Trip                           identify damaged equipment that must be repaired before the vehicle can be used again.
 Inspection”)                            •     The motor carrier must either (1) repair or replace the defective or damaged equipment, or (2) certify
                                               that repairs are not necessary before allowing the vehicle to be driven.
Source: GAO analysis of Federal Motor Carrier Safety Administration regulations. 49 C.F.R. §§ 396.17, 396.9, 392.7, 396.11. | GAO-19-264



                                                                  For fatal crashes, including fatal underride crashes, data are collected by
                                                                  law enforcement officials at the location of the crash, aggregated at the
                                                                  state level, and then transferred to NHTSA’s Fatality Analysis Reporting
                                                                  System (FARS). FARS is a census of all fatal traffic crashes in the U.S.
                                                                  When a fatal crash occurs, a state or local police officer typically
                                                                  completes a crash report form unique to each state. These forms can
                                                                  include a variety of data fields, such as the time of the crash, weather
                                                                  conditions, and the number of killed or injured persons. In the case of an
                                                                  underride crash, officers may indicate an underride crash occurred in a
                                                                  specific field for recording this crash type or in a narrative field. FARS
                                                                  analysts—state employees who are trained by NHTSA’s data validation
                                                                  and training contractor to code state crash data for input into FARS—in
                                                                  each state receive and analyze the data in the crash report forms in order
                                                                  to compile a record of the fatal crash. FARS analysts rely on the
                                                                  information within the crash report form in order to enter accurate data.

                                                                  To encourage greater uniformity of crash data, NHTSA, FMCSA, and
                                                                  other agencies and associations cooperatively developed the Model
                                                                  Minimum Uniform Crash Criteria (MMUCC) in 1998. The MMUCC
                                                                  guideline, currently in the fifth edition, identifies a minimum set of motor
                                                                  vehicle crash data elements and their definitions that states should
                                                                  consider collecting, but are not required to collect. The MMUCC is
                                                                  updated about every 4 to 5 years. Prior to publication of each edition, an
                                                                  expert panel from the relevant agencies and associations convenes to



                                                                  Page 9                                                                   GAO-19-264 Truck Underride Guards
                              review all proposed changes suggested by traffic safety stakeholders to
                              determine what will be included in the MMUCC. According to NHTSA
                              officials, the next updated version of the MMUCC is expected to be
                              issued in 2022.



Underride Crash
Fatalities Reported by
NHTSA Data Are
Relatively Low but
Are Likely
Undercounted

Although Reported             From 2008 through 2017, the annual number of fatalities resulting from
Underride Crash Fatalities    underride crashes involving one or more trucks reported in FARS ranged
                              between 189 and 253, resulting in an annual average of approximately
Represent a Small             219 fatalities (see table 2). 15 Comparatively, the FARS data show an
Percentage of Total Traffic   annual average of about 34,700 total traffic fatalities and approximately
Fatalities, Underride         4,000 fatalities involving large trucks over the same period. Therefore,
Crashes Present a             reported underride crash fatalities on average accounted for less than 1
Greater Risk of Fatalities    percent of total traffic fatalities and 5.5 percent of all fatalities related to
                              large truck crashes during this time frame.
or Serious Injuries




                              15
                                To be included in FARS, a crash must have involved a motor vehicle traveling on a
                              trafficway customarily open to the public, and must have resulted in the death of a motorist
                              or a non-motorist within 30 days of the crash. While stakeholders we spoke with noted the
                              factors described in this report that could lead to underreporting of fatalities related to
                              truck underride crashes, the failure to record a fatality that occurred subsequent to—but
                              within 30 days of—a crash could also be a factor in underreporting.




                              Page 10                                                GAO-19-264 Truck Underride Guards
Table 2: Reported Underride Crash Fatalities, Total Traffic Fatalities, and Large Truck Fatalities, 2008 through 2017

                                                                            Underride Crash                                        Underride Crash
                                                                              Fatalities as a                                         Fatalities as a
                         Underride Crash               Total Traffic     Percentage of Total           Total Large Truck        Percentage of Large
Year                           Fatalitiesa               Fatalities         Traffic Fatalities                 Fatalitiesb          Truck Fatalities
2008                                       198               37,423                       0.53%                        4,245                      4.66%
2009                                       211               33,883                       0.62%                        3,380                      6.24%
2010                                       221               32,999                       0.67%                        3,686                      6.00%
2011                                       189               32,479                       0.58%                        3,781                      5.00%
2012                                       247               33,782                       0.73%                        3,944                      6.26%
2013                                       210               32,893                       0.64%                        3,981                      5.28%
2014                                       213               32,744                       0.65%                        3,908                      5.45%
2015                                       253               35,485                       0.71%                        4,094                      6.18%
2016                                       196               37,806                       0.52%                        4,369                      4.49%
2017                                       253               37,133                       0.68%                        4,761                      5.31%
Average                                    219               34,663                       0.63%                        4,015                      5.49%
Source: GAO analysis of NHTSA data. | GAO-19-264
                                                   a
                                                    Reported underride crash fatalities include those fatalities in which a crash involved a medium or
                                                   heavy truck.
                                                   b
                                                    ”Large truck” is defined as any medium or heavy truck, excluding buses and motor homes, with a
                                                   gross vehicle weight rating greater than 10,000 pounds.


                                                   Although reported underride crash fatalities make up a small proportion of
                                                   total traffic fatalities, NHTSA officials told us that severe underride
                                                   crashes—involving passenger compartment intrusion—are more likely to
                                                   result in a fatality or serious injury than crashes in which the passenger
                                                   vehicle’s safety features engage and are able to protect the occupants.
                                                   Officials from four state DOTs we spoke to also stated that while
                                                   underride crashes are not common, the consequences—fatalities or
                                                   serious injuries, including head or neck injuries—are more likely to be
                                                   severe. An official from one state DOT noted that their agency did not
                                                   consider underride crashes to be a high priority issue. However, upon
                                                   further review of the state’s underride crash data, this official stated that
                                                   while underride crashes may occur infrequently, they present a higher risk
                                                   of fatality than the official had previously realized. An official in another
                                                   state told us they do not regularly review underride crash data but, upon
                                                   analysis of the data, found that underride crashes constituted a larger
                                                   percentage than they anticipated—16 percent—of all fatal large truck
                                                   crashes in the state in 2017.




                                                   Page 11                                                       GAO-19-264 Truck Underride Guards
NHTSA’s FARS data show that most of the reported underride crash
fatalities occurred when the crash impact was located at the rear or sides
of a trailer. From 2008 through 2017, approximately 45 percent (825 of
1836) of reported fatalities in underride crashes with a recorded point of
impact on the large truck occurred when the initial impact of the crash
was the rear of the trailer. About 32 percent (590 of 1836) of reported
underride crash fatalities were in crashes where the side of the trailer was
the point of initial impact. Approximately 21 percent (392 of 1836) of
reported underride crash fatalities were in crashes with the initial impact
at the front of the tractor. These 392 fatalities from crashes involving the
front of a tractor could be crashes in which the tractor impacted the rear
of a passenger vehicle but might also have occurred in a head-on
collision between the car and the tractor. The point of impact for underride
crash fatalities with passenger compartment intrusion—the most severe
form of underride—had similar distributions, with most reported fatalities
occurring when the initial point of impact was the rear or side of the
trailer. 16

State and local police officials we interviewed said that the underride
crash fatality cases they are familiar with occurred in high speed
scenarios, often exceeding 55 miles per hour. For example, officials
representing a state police department described scenarios in which
passenger vehicles traveling at high speeds rear-ended tractor-trailers
stopped on the highway’s shoulder or slowed for highway construction;
similar scenarios occurred when tractor trailers failed to slow for stopped
traffic and crashed into the rear of passenger vehicles. However, on
average, 62 percent of fatalities from underride crashes with passenger
compartment intrusion reported in 2008 through 2017 did not include a
reported speed. For example, for these fatalities in 2017, 72 percent had
speed coded in FARS as missing or not reported. A state and a local
police official told us that determining the speed of an underride crash can
be challenging due to the often severely damaged condition of the
passenger vehicle following an underride crash. Officials representing
state police said that they are better able to document whether or not
speeding was a factor in an underride crash, rather than an exact speed.

16
  Of the reported underride crash fatalities between 2008 and 2017 in which passenger
compartment intrusion occurred, approximately 46 percent (489 of 1062) occurred when
the initial point of impact was the rear of the trailer. Approximately thirty percent (323 of
1062) of these fatalities occurred when the initial point of impact was the sides of the
trailer, and about 23 percent (243 of 1062) when the initial point of impact was the front of
the tractor.




Page 12                                                 GAO-19-264 Truck Underride Guards
                            IIHS representatives also acknowledged the difficulty in documenting the
                            speed involved in an underride crash, and further stated that this difficulty
                            brings into question the accuracy of the speed data that are recorded in
                            FARS for underride crashes.

Variability in the Data     Stakeholders we interviewed told us that underride crash fatalities are
Collection Process Likely   likely underreported in FARS due to several factors, such as variability
                            across states in defining underride crashes, inconsistencies in state crash
Leads to Underreporting
                            reporting forms and documentation methods, and limited information
                            provided to state and local police on how to consistently identify and
                            record underride crash data. These factors could contribute to police
                            officers incorrectly and inconsistently documenting underride crash data
                            on the crash report form. As a result, FARS analysts may not have
                            sufficient information to properly categorize the crash as an underride,
                            ultimately affecting the number of underride crash fatalities identified in
                            FARS. Standards for Internal Control in the Federal Government notes
                            that management should use quality information to achieve the entity’s
                            objectives. 17 Underreporting of underride crashes would affect the quality
                            of NHTSA’s data, thereby affecting the agency’s ability to accurately
                            identify the magnitude of underride-related crashes and limiting its ability
                            to make informed decisions on rulemaking or other efforts that would help
                            the agency meet its mission to improve traffic safety.

                            Other researchers and organizations have also commented on the quality
                            of NHTSA’s underride crash data. For example, IIHS representatives told
                            us that they compared underride crash cases in FARS and in NHTSA’s
                            and FMCSA’s Large Truck Crash Causation Study—a study of large truck
                            crashes from 2001 through 2003—and identified some cases that
                            involved underride crashes but that were not categorized as such in
                            FARS. Consequently, IIHS representatives stated that they have used
                            more general rear impact crash data as a proxy for underride crashes due
                            to their finding that underreporting of underride crashes occurs in FARS.
                            Additionally, the University of Michigan’s Transportation Research




                            17
                              GAO, Standards for Internal Control in the Federal Government, GAO-14-704G
                            (Washington, D.C.: September 2014).




                            Page 13                                            GAO-19-264 Truck Underride Guards
                                 Institute reported that it can be difficult or impossible to identify underride
                                 in available computerized crash data files, such as FARS. 18

Variability in Underride Crash   State and local police officers do not use a standard definition of an
Definition                       underride crash when collecting data at the scene of a crash. NHTSA
                                 officials told us that the agency’s definition for an underride crash—”a
                                 vehicle sliding under another vehicle during a crash”—is found in the
                                 FARS coding and validation manual, a document primarily used by FARS
                                 analysts and researchers. The FARS coding and validation manual
                                 further distinguishes underride crashes as those with and without
                                 passenger compartment intrusion. The MMUCC, which includes
                                 definitions of various crash-related elements, does not include a definition
                                 of an underride crash. Among officials from the five state police
                                 departments we interviewed, underride crash definitions varied, even
                                 within states. For example, in one state, an official from one local police
                                 department said that a passenger vehicle would need to have over 50
                                 percent of its hood underneath the trailer to constitute an underride crash,
                                 while other officials within the state police used a broader definition
                                 consistent with NHTSA’s definition, i.e., a vehicle going underneath
                                 another vehicle by any amount. A state police official and a local police
                                 official we interviewed indicated that they would like a clearer definition of
                                 the conditions that constitute an underride crash to help them better
                                 identify these crashes. Further, representatives from NHTSA’s data
                                 validation and training contractor told us that when they have identified
                                 anomalous patterns in underride crash data in FARS, the main reason for
                                 these anomalies has been varying definitions of this crash type, as
                                 reporting officers have many interpretations of what constitutes an
                                 underride crash. 19 A standard definition of an underride crash, for
                                 example in the MMUCC, would provide greater assurance that underride
                                 crashes are accurately recorded.



                                 18
                                  Blower, D., Woodrooffe, J., Page, O., Analysis of Rear Underride in Fatal Truck
                                 Crashes, 2008. (Ann Arbor, MI: US DOT HS 811 652, 2012). The underride crash data
                                 were collected as a supplement to the 2008 Trucks Involved in Fatal Accidents survey,
                                 which in turn supplements NHTSA’s FARS file.
                                 19
                                   NHTSA’s data validation and training contractor specializes in training and data quality
                                 control support for NHTSA. The contractor supports NHTSA’s FARS data collection
                                 program, specifically in the delivery and maintenance of the FARS training program and
                                 data manuals, and assists NHTSA in quality control and review of data added by FARS
                                 analysts.




                                 Page 14                                                GAO-19-264 Truck Underride Guards
Inconsistency in State Crash   While all states have a crash report form to gather data following a crash,
Reporting Forms and            these state forms vary in whether and how underride crash-related
Documentation of Underride     information is collected. Specifically, for the most recent crash report
Crashes                        forms we examined from the 50 states and the District of Columbia, as of
                               October 2018:

                               •   17 state forms have a specific field for “Underride.” Eleven of these
                                   forms also have data fields for passenger compartment intrusion.
                               •   32 state forms have a point of impact or area damaged field for
                                   “undercarriage.” The point of impact field is generally intended to be
                                   used to indicate the locations of initial impact or area that was
                                   damaged for all vehicles involved in the crash. Some state police and
                                   transportation officials we spoke with noted that this field could be
                                   used to indicate that an underride crash occurred, as the initial point
                                   of impact on a large truck could be the undercarriage in such a crash.
                               •   Two states, California and Hawaii, do not have a data element related
                                   to underride crashes or undercarriage on their state crash report
                                   forms.

                               The presence of an underride field in state crash report forms may affect
                               the extent to which underride crash fatalities are captured in FARS. For
                               example, we observed that after a state revised its form to remove the
                               underride field, the number of reported underride crash fatalities
                               significantly decreased, potentially indicating that underride crashes were
                               being underreported after the change. Conversely, in another state, we
                               observed that the number of reported underride crash fatalities
                               significantly increased following the addition of an underride field to the
                               crash report form, potentially indicating that underride crashes were being
                               reported more accurately following the change.

                               States have their own discretion to develop crash report forms based on
                               several factors that may be particular to each state. For example, states
                               include or exclude certain data elements on their crash report forms
                               based on the traffic safety priorities within that state. Officials we
                               interviewed from two state police departments told us that they do not
                               have an underride field on their crash report forms because underride
                               crashes are not a traffic safety priority for them. In another state, state
                               DOT officials told us that they chose to include an underride field on the
                               crash report form to better align with the FARS data fields, including those
                               fields related to underride. States may include certain data elements on
                               their crash report form based on the recommended data elements in the
                               MMUCC. However, while the MMUCC was developed to encourage



                               Page 15                                       GAO-19-264 Truck Underride Guards
greater uniformity of crash data, its guidelines are voluntary, and it does
not currently include references to underride or override crash data
elements. In its June 15, 2017, report, the Post-Accident Report Advisory
Committee—a group appointed by the FMCSA Administrator to provide
input on additional data elements to be included in police accident reports
involving commercial motor vehicles—suggested that MMUCC data
elements be updated to include a collection of information about whether
underride and override are involved in a crash. However, according to the
MMUCC’s standard development process and NHTSA officials, to adopt
new data elements, the entire MMUCC expert panel—which is comprised
of stakeholders representing NHTSA, FMCSA, the Governors Highway
Safety Association, states, data collectors, data managers, data users,
and safety stakeholders—must reach at least 70 percent agreement for
approval of new changes to the MMUCC. Under the MMUCC’s standard
development process, the MMUCC expert panel will consider
recommendations and proposed changes to the MMUCC guidelines,
including those proposed by NHTSA in the months preceding the next
MMUCC update in 2022.

In states that do not include a specific underride crash field in the state
crash report form, state and local police officers we interviewed told us
that officers responding to a crash may describe underride crashes in the
diagram or narrative fields of the form. However, these officers said that a
police officer may inappropriately document an underride crash as a rear
impact crash. Similarly, officers may categorize the crash as both an
underride and an override crash, which NHTSA’s FARS coding and
validation manual indicates would be incorrect. Selected state officials
told us that unless the officer documenting the crash specifically
describes an underride crash in the narrative field, FARS analysts at the
state level who review the crash report forms will not have the information
to know if a crash involved underride.

Police officers we interviewed in states that include “undercarriage” rather
than a specific underride crash field in the crash report form told us that
they may use the option as a proxy for an underride crash; however, this
field may be used inconsistently. For example, in one state, state police
officers said they would select “undercarriage” on the crash report form to
reflect an underride crash, whereas a local police officer in the same state
said that local officers would not use that field to identify an underride
crash occurred and, instead, would document the underride crash in the
narrative. NHTSA’s data validation and training contractor told us that it is
not a recommended practice for officers to select “undercarriage” as a
proxy for underride crashes, noting that this inconsistency could lead to


Page 16                                       GAO-19-264 Truck Underride Guards
                                  inaccuracies in the resulting FARS data. Including underride as a
                                  recommended data field in the MMUCC would provide greater assurance
                                  that underride crashes are accurately recorded.

Limited Information Provided to   State and local police officials we interviewed said that they receive
Police                            limited or no training on how to identify and record information for
                                  underride crashes. Officials from all five state police departments we
                                  spoke with said that they develop their own crash reporting training for
                                  police. This training emphasizes overall crash reporting with a limited
                                  focus, if any, on underride crashes. An official representing one state
                                  police office said that the state police provide training on how to complete
                                  crash reports and general traffic safety, whereas FARS analysts—often
                                  within the state DOT—are concerned with the quality of data collection for
                                  data analysis purposes, which is not a primary focus of law enforcement
                                  training. State and local police officials we interviewed said they generally
                                  have limited to no follow-up or continuous training on crash reporting
                                  beyond initial police academy training. Local police we interviewed also
                                  told us that while they develop and implement their own crash report
                                  training, they may also receive training from the state police. Some state
                                  police officers that we spoke with said that they conduct training for local
                                  police departments when requested. One local police official we spoke
                                  with said that officers have limited exposure to underride crashes in these
                                  training sessions and that the average officer would likely not know how
                                  to appropriately identify an underride crash. Officials we spoke with from
                                  three state and two local police departments stated that additional
                                  information to police departments on underride crashes could help
                                  improve data collection and overall traffic safety.

                                  NHTSA provides training to FARS analysts on reviewing crash report
                                  forms and appropriately inputting data in FARS, but does not provide
                                  information on crash data collection to state and local police who initially
                                  collect the data. According to NHTSA’s data validation and training
                                  contractor, the contractor trains FARS analysts on identifying underride
                                  crashes. Specifically, the contractor trains FARS analysts to review the
                                  crash report forms for sufficient detail to meet the definition of an
                                  underride crash and determine if a crash involved underride for entry in
                                  FARS. NHTSA officials told us that it is the responsibility of state police
                                  academies to train law enforcement officers to conduct on-site
                                  investigations and complete crash report forms. NHTSA officials said that
                                  they do not currently provide underride identification information directly
                                  to state and local police who initially collect the crash data. However,
                                  NHTSA does provide information to state and local police on other topics,
                                  such as improving traffic safety and driver behavior, for example through


                                  Page 17                                       GAO-19-264 Truck Underride Guards
                       DOT’s Enforcement and Justice Services Division. NHTSA officials
                       acknowledged that it would be feasible to also provide information on
                       identifying and recording underride crashes. Standards for Internal
                       Control in the Federal Government notes that management
                       communicates quality information externally through reporting lines so
                       that external parties can help the entity achieve its objectives and address
                       related risks. 20 By providing information to state and local police
                       departments—such as materials or instruction on the definition of an
                       underride crash and how to appropriately document these crashes—
                       NHTSA could improve the quality and completeness of underride crash
                       data that police collect.


                       Underride guards for the rear, side, and front of tractor-trailers and single-
Underride Guards Are   unit trucks are in varying stages of development. NHTSA has issued an
in Varying Stages of   NPRM proposing to strengthen rear guard requirements for trailers, and
                       estimates that about 95 percent of all newly manufactured trailers already
Development, and       meet the stronger requirements. While FMCSA requires commercial
Gaps Exist in          vehicles to be inspected to ensure they are safe, rear guards may not be
                       regularly inspected. Side underride guards are being developed, but
Inspection and         stakeholders identified challenges to their use, such as the stress on
Research               trailer frames due to the additional weight. NHTSA has not performed
                       research on the overall effectiveness and cost of these guards, and
                       manufacturers we interviewed told us that they are hesitant to invest in
                       developing side underride guards without such research. In response to a
                       2009 crash investigation, the National Transportation Safety Board
                       (NTSB) recommended that NHTSA require front guards on tractors.
                       NHTSA officials stated that the agency plans to complete research to
                       respond to this recommendation in 2019. However, stakeholders
                       generally stated that the bumper and lower frame of tractors typically
                       used in the U.S. may mitigate the need for front guards for underride
                       purposes. NTSB has further recommended that NHTSA develop
                       standards for crashworthy underride guards for single-unit trucks—such
                       as dump trucks—but NHTSA recently concluded that these standards
                       would not be cost effective.




                       20
                        GAO-14-704G.




                       Page 18                                        GAO-19-264 Truck Underride Guards
Most Newly Built Trailers   All seven of the eight largest trailer manufacturers—which are responsible
Are Equipped with Rear      for about 80 percent of the trailers on the road in the U.S.—we spoke with
                            told us that they have been building to the stronger Canadian rear guard
Guards That Exceed
                            standard since those requirements became effective in 2007. Some
NHTSA Requirements          manufacturers said that since trucking company operations may span the
                            border between Canada and the U.S., it was easier to build to a single
                            standard rather than manufacture trailers that comply with either the
                            Canadian requirements or the U.S. requirements. NHTSA is considering
                            strengthening the U.S. requirements for rear guards to align with the
                            Canadian rear guard standards. As part of the 2015 NPRM on
                            strengthening the U.S. requirements to the level of the Canadian
                            standards, NHTSA estimated that 93 percent of all newly manufactured
                            trailers in the U.S. are already equipped with a rear guard that meets the
                            Canadian standard. In July 2018, NHTSA officials told us that figure had
                            increased to 95 percent of all newly manufactured trailers, with the
                            remaining 5 percent from smaller manufacturers who may not wish to
                            incur the additional cost or weight of a Canadian-style rear guard.
                            Trucking industry stakeholders told us that the average lifecycle of a
                            trailer varies: one said the lifespan is 10 to 15 years and another stated a
                            12-year lifespan.

                            NHTSA performed a cost-benefit analysis as part of the 2015 NPRM in
                            which it preliminarily estimated that requiring newly manufactured trailers
                            to include rear guards built to the new standard would be cost-beneficial.
                            Specifically, NHTSA’s analysis found that the cost of a rear guard that
                            meets the Canadian standard was approximately $500 per trailer, which
                            was $229 more than a guard that complies with the existing U.S.
                            requirement. NHTSA’s analysis also found that a Canadian-style rear
                            guard was heavier than its U.S. counterpart. The rear guard NHTSA
                            studied that complies with current U.S. regulations weighed 172 pounds,
                            whereas those meeting the Canadian standard weighed between 191 and
                            307 pounds. Regarding benefits, NHTSA estimated in 2015 that—
                            accounting for the trailers that already meet the stronger standard—
                            adopting the Canadian standard would prevent about one fatality and
                            three serious injuries per year. According to DOT, these estimates may
                            have since changed, as a higher percentage of trailers are now
                            manufactured to meet the Canadian standards. Comments on this NPRM
                            varied. Some comments were in support of the measure, citing the safety
                            benefits. Other comments noted that automated driver assistance




                            Page 19                                       GAO-19-264 Truck Underride Guards
technology may offer better outcomes. 21 Further, some comments called
for NHTSA to take additional steps to improve the safety capabilities of
rear guards, such as allowing fewer exemptions from compliance. NHTSA
has not taken action on this NPRM since it was proposed in December
2015. NHTSA officials we interviewed could not provide information on
when the NPRM would move forward.

The largest trailer manufacturers have also taken steps to further improve
the design of rear guards to prevent underride crashes in a range of
scenarios. Because IIHS found that the weakest points for rear guards
are generally the outer edges furthest from the center of the guard, it
created a procedure to test the ability of rear guards to withstand crashes
at different overlap points, starting at the center of the guard and moving
closer to the endpoints. Specifically, this procedure involves three crash
tests using full width, 50-percent, and 30-percent overlap of the front of
the car with the rear guard, as depicted in figure 4. According to IIHS, as
of September 2018, all of the top eight trailer manufacturers operating in
the U.S. have successfully passed these tests. Some of these
manufacturers provide the improved rear guards as a standard feature on
all new trailers, while others offer them as an option for purchase.




21
  These technologies allow vehicles to perform certain driving tasks without human input
and encompass a diverse range of automated technologies ranging from relatively simple
driver assistance systems to fully self-driving vehicles. See GAO, Automated Vehicles:
Comprehensive Plan Could Help DOT Address Challenges, GAO-18-132 (Washington,
D.C.: Nov. 30, 2017).




Page 20                                              GAO-19-264 Truck Underride Guards
Figure 4: Insurance Institute for Highway Safety Rear Guard Testing Procedure at Full Width, 50 Percent Overlap, and 30
Percent Overlap




                                         In addition to strengthening rear guards on trailers, advancements in
                                         automatic braking systems in passenger vehicles may help reduce the
                                         frequency of underride crashes. These systems, though not federally-
                                         required, have been available and installed in some passenger vehicles
                                         and tractors and are designed to detect objects or other vehicles in front
                                         of the vehicle and automatically apply the brakes to avoid or lessen the
                                         severity of an impact. According to NHTSA, twenty automakers
                                         representing more than 99 percent of the U.S. automobile market have
                                         agreed to make automatic braking systems a standard feature on newly-
                                         built passenger vehicles starting in 2022. These braking systems may
                                         help reduce the number of passenger vehicles striking the rear of tractor-
                                         trailers, potentially reducing the frequency of underride-related crashes,
                                         fatalities, and injuries.


Rear Guards in Use on                    FMCSA regulations require commercial vehicles operating in interstate
Roads May Not Be                         commerce to be inspected to ensure they are safe. However, the rules do
                                         not specifically include an inspection of the rear guard. After a rear guard
Regularly Inspected
                                         has been installed on a new trailer, stakeholders told us that the guard
                                         may be damaged during normal use (see fig. 5), for example by backing
                                         into loading docks. However, only certain roadside inspections—which
                                         are performed at random or if an officer suspects a problem—specifically
                                         require the rear guard to be inspected. Specifically, of the eight types of



                                         Page 21                                            GAO-19-264 Truck Underride Guards
roadside inspections, representatives of the Commercial Vehicle Safety
Alliance (CVSA)—which helps develop roadside inspection standards—
told us that four require the rear guard to be inspected. 22

Figure 5: Example of a Damaged Rear Guard




Stakeholders we interviewed told us that a trailer could go its entire
lifecycle—estimated as typically 10 to 15 years—without ever being
selected for a roadside inspection. FMCSA data show that although rear
guard violations may be identified during roadside inspections, they
constitute a small percentage of all violations. For example, out of about
5.8 million violations identified during roadside inspections in 2017,
approximately 2,400, or 0.042 percent, were rear guard violations. In an
effort to learn more about rear guard violations, CVSA encouraged

22
  A fifth type of roadside inspection, known as “Level 4 – Special Inspections,” is
performed to review one piece of equipment, such as air brakes. Representatives from
CVSA, which helps develop roadside inspection standards, stated that a special
inspection could potentially be set up to solely inspect rear guards.




Page 22                                              GAO-19-264 Truck Underride Guards
commercial vehicle inspectors to specifically focus on rear guards during
their roadside inspections performed from August 27 through 31, 2018.
According to these data, for the more than 10,000 trailers inspected
during that 5-day time frame, about 900 violations (about 28 percent of all
violations identified) for rear guard dimensional or structural requirements
were identified, including almost 500 instances where the rear guard was
cracked or broken, or missing altogether. 23 A CVSA representative stated
there was a greater percentage of violations identified because inspectors
were asked to specifically focus on the rear guard during this effort.

Inspectors performing annual inspections—which can include employees
of the motor carrier—rely on a checklist established in FMCSA
regulations, known as “Appendix G.” This appendix specifies what
equipment must be inspected, such as the brake system, lighting, and
wheels. Appendix G does not list the rear guard as an item to be
inspected. 24 In August 2018, CVSA petitioned FMCSA to amend
Appendix G to include rear guards as an item to be inspected. According
to CVSA, in September 2018, FMCSA provided acknowledgment of its
intent to review CVSA’s petition.

FMCSA’s regulations, including those regarding commercial vehicle
inspections, help the agency achieve its safety mission of reducing
crashes, injuries, and fatalities. Further, Standards for Internal Control in
the Federal Government notes that management should use quality
information to achieve the entity’s objectives. 25 Prior to receiving CVSA’s
petition to amend Appendix G, FMCSA officials told us that not including
rear guards in Appendix G does not affect commercial vehicle safety, as
FMCSA regulations require all parts and accessories specified within the
regulations—which includes the rear guard—to be in safe and proper
operating condition at all times. According to DOT, the agency does not
believe that motor carriers are ignoring the application of these
regulations to rear guards. However, without explicitly including the
inspection of the rear guard in Appendix G, there is no assurance that
rear guards in operation will be inspected at least annually to ensure they

23
  10,112 trailers were inspected during this time frame, including 1,072 trailers
manufactured prior to January 26, 1998—the date when NHTSA’s rulemaking requiring
crashworthy rear guards on newly built tractor-trailers went into effect.
24
 49 C.F.R., Appendix G to subchapter B of Chapter III.
25
  GAO, Standards for Internal Control in the Federal Government, GAO-14-704G
(Washington, D.C.: September 2014).




Page 23                                              GAO-19-264 Truck Underride Guards
                             perform as designed to prevent or mitigate an underride crash. This
                             omission potentially affects FMCSA’s safety mission to help ensure the
                             safe operation of tractor-trailers on the nation’s highways.


Side Underride Guards        While not currently required in the U.S., crashworthy side underride
Are Being Developed, but     guards are being developed which could entail both costs and benefits to
                             society. For example, there is currently one IIHS-crash-tested aftermarket
Limited Information Exists
                             manufacturer of side underride guards in North America, which has sold
to Assess Overall            about 100 sets of side underride guards. According to the manufacturer,
Effectiveness and Cost       the cost of the guards starts at about $2,500 per trailer, though the price
                             could decrease in the future as the manufacturing process becomes more
                             efficient and greater quantities are built and sold. These side underride
                             guards have been crash-tested by IIHS and successfully prevented
                             underride crashes in tests at 35 and 40 miles per hour. As a result, the
                             benefits of such guards might include a reduction in the number of
                             fatalities in underride crashes. The manufacturer estimated that more
                             widespread use of side underride guards would occur over the next 3 to 5
                             years. However, the manufacturer also said that more information on how
                             side underride guards might affect everyday operations is needed before
                             more widespread adoption by the industry. Additionally, some trailer
                             manufacturers told us that they are in the process of developing side
                             underride guards, but none are currently available for purchase. For
                             example, a representative from one trailer manufacturer developing its
                             own side underride guards estimated that it would be feasible to have
                             these guards designed, tested, and available for sale within the next 2
                             years. However, the representative said that the manufacturer is hesitant
                             to invest additional resources because of uncertainty about potential
                             future regulatory requirements. Specifically, the manufacturer does not
                             want to invest additional resources to develop a side underride guard that
                             might later have to be redesigned to meet federal requirements, if such
                             requirements were to be established and to differ from the manufacturer’s
                             design specifications.

                             Representatives from several trailer manufacturers, trucking industry
                             organizations, and police departments we spoke with cited challenges
                             with the use of side underride guards that would need to be addressed
                             prior to widespread adoption by the industry. Officials from Canada and
                             the European Union—which also do not require the use of side underride
                             guards that can withstand the force of a vehicle crash—noted similar
                             challenges.




                             Page 24                                      GAO-19-264 Truck Underride Guards
•   Weight: According to the aftermarket side underride guard
    manufacturer, the side underride guards currently available for sale
    weigh between 575 to 800 pounds in total. Representatives from two
    trucking industry organizations we spoke with stated that the
    additional weight from side underride guards may require carriers to
    put more trailers on the roads to ship goods in order to stay under
    federal maximum weight restrictions (generally 80,000 pounds).
    Federal regulations allow for certain exemptions in the federal weight
    limits, such as for auxiliary batteries. Some stakeholders also stated
    that the additional weight from side underride guards would increase
    fuel costs (assuming all else remains the same) and could put stress
    on the trailer’s frame, reducing its lifespan and potentially increasing
    maintenance costs.
•   Road clearance: Some stakeholders we interviewed—including two
    trucking industry organizations, a tractor-trailer fleet operator, and a
    trailer manufacturer—stated that side underride guards limit a trailer’s
    clearance from the ground, which could limit the geographic locations
    that could be serviced by a trailer or—if the guards drag along the
    ground—result in damage to the guards or even the trailer. Conditions
    involving limited clearance could include traveling over raised railroad
    crossings or navigating sloped loading docks. While aerodynamic side
    skirts may also drag along the ground in similar conditions, they are
    more flexible than side underride guards and less likely to damage the
    trailer.
•   Effects on under-trailer equipment and access: Installation of a side
    underride guard may limit access to or displace equipment currently
    underneath a trailer, including spare tires, fuel tanks, and
    aerodynamic side skirts. Additionally, the rear axles of some trailers
    can be adjusted to evenly distribute the weight of the trailer’s cargo.
    For example, trailer manufacturers told us that when the axle is
    moved to the furthest rear position of the trailer, a fixed-length side
    underride guard could leave a gap large enough for a car to still have
    an underride crash. Further, some police officers we interviewed told
    us that it could be challenging to perform roadside inspections of
    trailers equipped with side underride guards because the guards
    could limit access to the underside of the trailer.
Representatives from three trucking industry organizations we spoke with
indicated that crash avoidance technologies may be more effective than
underride guards at minimizing underride crashes, including side
underride crashes. However, while these technologies have the potential
to mitigate crashes, it is unlikely that they will be available on a more
widespread scale in a time frame soon enough to render underride



Page 25                                       GAO-19-264 Truck Underride Guards
guards unnecessary. While automatic braking systems for passenger
vehicles are to become a standard feature on newly built vehicles starting
in 2022, IIHS representatives told us that these systems are less effective
at detecting and mitigating side crashes than rear or frontal crashes.
Specifically, the representatives stated that automatic braking systems
would not be effective in situations where the passenger vehicle impacts
the side of a trailer at an oblique angle rather than at a perpendicular
angle. According to stakeholders we interviewed, it will take a
considerable amount of time for the passenger fleet to adopt automated
vehicle technologies, with some stating that there will be a mix of
automated and non-automated technologies on the nation’s highways for
decades—longer than the 3 to 5 years estimated by the side underride
guard manufacturer for more widespread use of these guards. 26

NHTSA recently issued a study on the safety performance of certain
materials used for side underride guards. 27 However, NHTSA has not
performed research on the overall effectiveness and costs associated
with or the design of side underride guards. NHTSA’s mission is to “save
lives, prevent injuries and reduce economic costs due to road traffic
crashes, through education, research, safety standards and enforcement
activity.” 28 Additionally, a statement of federal principles on regulatory
planning and review indicates that in deciding whether and how to
regulate, agencies should assess all costs and benefits of available
alternatives, including the alternative of not regulating, and that the
agency should base its decisions on the best reasonably obtainable
scientific, technical, economic, and other information. 29 Additional
research on the effectiveness and cost associated with side underride
guards could better position NHTSA to determine whether these guards
should be required and, if so, appropriate standards for their


26
  We have previously reviewed DOT’s approach to automated vehicles and
recommended that the department develop a comprehensive plan for addressing
associated challenges. DOT agreed with our recommendation and has begun to take
actions to implement it. See GAO, Automated Vehicles: Comprehensive Plan Could Help
DOT Address Challenges, GAO-18-132 (Washington, D.C.: Nov. 30, 2017).
27
 NHTSA, Computer Modeling and Evaluation Of Side Underride Protective Device
Designs, DOT HS 812 522 (Washington, D.C.: April 2018).
28
  NHTSA, The Road Ahead: National Highway Traffic Safety Administration Strategic Plan
2016-2020, DOT HS 812 343 (Washington, D.C.: October 2016).
29
 Exec. Order No. 12866, 58 Fed. Reg. 51735 (Oct. 4, 1993).




Page 26                                             GAO-19-264 Truck Underride Guards
                                          implementation. Such research may also help provide information to
                                          address the challenges stakeholders cited with side underride guards.


Stakeholders Generally                    In general, there are two types of tractors used in tractor-trailer
Agreed That North                         combinations: conventional tractors, wherein the tractor is lower to the
                                          ground and the engine is in front of the cab where the driver sits, and
American Tractor Designs
                                          “cab-over” tractors, which are designed so the driver sits atop the engine
May Mitigate the Need for                 (see fig. 6). Conventional tractors are generally used in North America,
Front Guards for                          whereas cab-over tractors are used more frequently in the European
Underride or Override                     Union.
Purposes
Figure 6: Examples of a Conventional Tractor (left) and Cab-Over Tractor (right)




                                          Since 2000, the European Union has required tractors to include front
                                          guards to improve the protection of passengers in cars involved in head-
                                          on collisions with tractors. These guards are designed to lower the front
                                          profile of a cab-over tractor to be more compatible with that of a




                                          Page 27                                      GAO-19-264 Truck Underride Guards
passenger vehicle to reduce the potential for underride or override, and to
help absorb the force of a collision. 30

Some conceptual designs for front guards on conventional tractors have
been proposed by researchers in the U.S., but there are no designs
available for purchase or installation as there are for side underride
guards. Some research organizations have developed computer models
of front guards, but these guards have not been produced for U.S. tractor
configurations. Representatives from three trucking associations we
spoke with stated that their members were not researching, producing, or
installing front guards. A government official from Canada—where the
conventional tractor design is also commonly used—said that they did not
know of any tractor manufacturers or truck fleets that use front guards.
Representatives from a tractor manufacturer that operates in both the
U.S. and the European Union told us that front guard designs currently
used in the European Union would not be compatible with conventional
tractors used in the U.S., stating that these guards would need to be
installed in the same space that the bumper, frame, and some
equipment—including crash avoidance technologies—already occupy.

The design of conventional tractors may mitigate the need for front
guards for underride or override purposes, as the lower bumpers and
frame make the height of conventional tractors more compatible with
passenger cars. A 2013 NHTSA study found that tractors with lower
bumper heights were less likely to be involved in an override crash than
those with higher bumper heights. 31 Government officials from the
European Union told us that they did not see the need for conventional
tractors to have front guards, since the lower bumpers essentially function
as guards in frontal crashes. Officials from a state DOT, a state police
department, and a local police department all stated that they do not see
the need for front guards because the tractor is already so low to the
ground.

Further, state and local officials we spoke with noted that the front
underride crashes they have seen often occurred at higher speeds, such
30
  We focused our review of front guards on their use to prevent or mitigate underride or
override crashes. Our work did not evaluate the force absorption capabilities or general
crashworthiness of tractors in the U.S. or elsewhere.
31
  NHTSA, Heavy-Vehicle Crash Data Collection And Analysis to Characterize Rear and
Side Underride and Front Override in Fatal Truck Crashes, DOT HS 811 725
(Washington, D.C.: March 2013).




Page 28                                                GAO-19-264 Truck Underride Guards
as when a truck fails to stop for congested traffic or in a head-on collision
at higher speeds. In these cases, the speed combined with the much
greater weight of the truck could cause the truck to override the car (in the
first scenario) or the car to underride the tractor (in a head-on collision).
According to these officials, the force of the crash at those speeds—
regardless of whether there was underride or override—would very likely
be unsurvivable.

Additionally, automatic braking systems in tractors and passenger
vehicles may further mitigate the need for front guards for underride or
override purposes. These technologies—which, according to a tractor
manufacturer we interviewed, have been available and installed in some
tractors—can potentially stop a tractor from, for example, overriding a
passenger vehicle by automatically applying brakes in situations where a
potential rear-end collision is detected. Representatives from a tractor
manufacturer told us that about 70 to 80 percent of all newly
manufactured tractors it produced are equipped with these braking
systems and estimated that more than 50 percent of newly built tractors
sold by all manufacturers in the U.S. include these systems. Additionally,
front guard researchers we spoke with told us that some front underride
guard systems would be optimally effective when paired with automated
technologies, such as automatic braking systems.

While stakeholders generally agreed that North American tractor designs
may mitigate the need for front guards for underride or override purposes,
NTSB has called for greater use of front guards. Specifically, in 2010,
NTSB recommended that NHTSA, among other things, develop
performance standards for front guards and, after doing so, require all
newly manufactured trucks weighing more than 10,000 pounds to install
these front guards. NTSB issued these recommendations based on its
investigation of a June 2009 multi-car crash on an Oklahoma interstate, in
which the driver of a tractor trailer failed to slow down for traffic stopped
on the roadway. NTSB reported that the tractor-trailer’s high impact
speed and structural incompatibility with the passenger vehicles
contributed to the severity of the crash. As of December 2018, NHTSA
had not implemented NTSB’s recommendations. NHTSA reported to
NTSB in 2014 that it was in the process of conducting further examination
of crash data, but that efforts in developing standards for front guards are
a secondary priority to upgrading rear guard standards. NTSB stated that
NHTSA’s response was disappointing and that it continues to believe that
NHTSA actions are needed to implement this recommendation.
Additionally, NTSB recommended in 2015 that NHTSA develop
performance standards and protocols for assessing forward collision


Page 29                                       GAO-19-264 Truck Underride Guards
                           avoidance systems in commercial vehicles, which could also help to stop
                           a tractor from overriding a passenger vehicle. According to NTSB,
                           although NHTSA has performed some research on this technology, NTSB
                           has deemed NHTSA’s responses as unacceptable. NHTSA officials told
                           us that the agency anticipates completing relevant research and testing in
                           2019 that would give the agency the information it needs to make
                           appropriate decisions on next steps related to these NTSB
                           recommendations.


The Wide Variety of        FMCSA regulations require rear guards for certain single-unit trucks, such
Single-Unit Truck          as delivery or dump trucks, that are more than 30 inches above the
                           ground. However, according to representatives of the trucking industry we
Configurations Creates
                           interviewed as well as NTSB, the wide variety of single-unit trucks makes
Challenges for             it challenging to develop a one-size-fits-all requirement for underride
Implementing Crashworthy   guards. Single-unit trucks can vary widely with respect to weight,
Underride Guards           dimensions, and purpose and can include large pick-up trucks, fire trucks,
                           and dump trucks. The FMCSA regulations exempt certain single-unit
                           trucks—such as those already low to the ground—from the requirement
                           to have a rear guard if the vehicle is constructed and maintained such
                           that the body or other parts of the vehicle provide rear end protection
                           comparable to rear guards required for other single-unit trucks.

                           A trucking industry representative we spoke with said that his association
                           was not aware of any manufacturers currently designing or planning to
                           design crashworthy rear, side, or front underride guards for single-unit
                           trucks due to the variability of single-unit truck design. Some U.S. cities,
                           such as Boston, require pedestrian/cyclist side guards be installed on
                           municipally owned single-unit trucks, but these guards are not designed
                           to mitigate a passenger vehicle underride crash.

                           Research shows that crashes involving single-unit trucks occur less often
                           and are less likely to cause serious injuries and fatalities than those
                           involving tractor-trailers. For example, a 2013 NTSB study of crash data
                           from 2005 through 2009 found that single-unit truck crashes occurred less
                           often, resulted in fewer fatalities, and were less likely to cause serious




                           Page 30                                       GAO-19-264 Truck Underride Guards
injuries than tractor-trailer crashes. 32 NHTSA has also acknowledged that
single-unit trucks represent the majority of the registered heavy vehicle
fleet, but account for a lower percentage—27 percent—of rear end
fatalities.

To help address fatalities associated with underride crash fatalities
involving single-unit trucks, as part of its 2013 study, NTSB
recommended that NHTSA develop standards for crashworthy rear, side,
and front guards for single-unit trucks, as well as devote efforts to crash
avoidance technologies and include more variables in FARS to improve
data collection. NTSB also noted that, because of the variability in vehicle
design and cargo body styles, safety countermeasures for single-unit
trucks would need to be adapted for different truck types to address
technical challenges to their implementation.

NHTSA published an ANPRM in 2015 that considered requiring rear
guards with strength and energy absorption criteria for all newly built
single-unit trucks. However, NHTSA subsequently found that the costs of
this requirement outweighed the benefits. 33 Comments on this ANPRM
varied. For example, the American Trucking Associations stated that it
believed NHTSA underestimated the costs associated with installing
crashworthy rear guards for single-unit trucks. In contrast, IIHS, in its
comments on the ANPRM, questioned NHTSA’s assumptions and stated
that the agency was undervaluing the benefits and overestimating the
costs. Specifically, IIHS noted that NHTSA overestimated the additional
weight of the rear guards, thereby overestimating the cost by about 35 to
40 percent. IIHS also stated that due to concerns with the underlying
data, NHTSA underestimated the number of crashes into the rear of
32
  NTSB, Crashes Involving Single-Unit Trucks that Resulted in Injuries and Deaths,
NTSB/SS-13/01, PB2013-106637 (Washington, D.C.: June 17, 2013). For the crashes
and fatalities information, NTSB used 2005 through 2009 data from the Trucks in Fatal
Accidents database. For the serious injuries information, NTSB used 2005 through 2009
data from the Crash Outcome Data Evaluation System for the following states: Delaware,
Maryland, Minnesota, Nebraska, and Utah. Additional research from IIHS using 2010
FARS data found that 75 percent of deaths in large truck crashes in 2010 were in crashes
involving tractor-trailers whereas 25 percent were in crashes involving single-unit trucks.
IIHS, “Fatality Facts: Large Trucks, 2010,” accessed October 24, 2018,
http://www.iihs.org/iihs/topics/t/large-trucks/fatalityfacts/large-trucks/2010.
33
  NHTSA’s cost-benefit analysis included in the ANPRM considered the effects of
requiring rear guards with strength and energy absorption capabilities on newly built
single-unit trucks for class 3 (e.g., delivery trucks) through class 8 (e.g., dump trucks).
NHTSA estimated that this requirement would not be cost-effective, even if class 3 single-
unit trucks were excluded from the analysis.




Page 31                                                GAO-19-264 Truck Underride Guards
              single-unit trucks with passenger compartment intrusion. NHTSA officials
              told us that they disagreed with IIHS’s assessment and stated that the
              data NHTSA used in the ANPRM were valid and appropriate. The
              ANPRM also considered requiring single-unit trucks to install red and
              white retroreflective tape meant to increase the visibility of these trucks,
              especially in the dark. NHTSA found that this requirement would be cost-
              effective at preventing or mitigating crashes involving single-unit trucks.
              However, NHTSA has since withdrawn the ANPRM, stating that—based
              on the comments received as well as analysis of the petitions—the
              changes being considered were not justified.


              The likely underreporting of underride crashes and fatalities due to
Conclusions   variability in the data collection process limits NHTSA’s ability to
              accurately determine the frequency of such crashes. An underride field in
              MMUCC and additional information from NHTSA on how to identify and
              record these crashes would provide greater assurance that state and
              local police officers are accurately reporting data on underride crashes.
              Such reporting would, in turn, enable NHTSA to better identify and
              support measures—such as rulemakings and research efforts—to help
              address this issue. While the stronger rear guards being voluntarily
              implemented by the largest trailer manufacturers show promise in
              mitigating the potentially devastating effects of rear underride crashes,
              rear guards will only be effective if they are properly maintained and
              replaced when damaged. The lack of specific requirements that rear
              guards be inspected annually for defects or damage potentially affects the
              safety of the traveling public and FMCSA’s ability to achieve its safety
              mission. Finally, designs of crashworthy side underride guards show
              promise at mitigating underride crashes, but manufacturers may be
              reluctant to move forward with further development of these types of
              guards without information from NHTSA on the effectiveness, cost, and
              implementation standards for these devices. With additional research on
              resolving the challenges associated with side underride guards, these
              guards may be closer to being a feasible solution than automated driver
              assistance technologies designed to prevent or mitigate side impacts that
              could lead to an underride crash.




              Page 32                                       GAO-19-264 Truck Underride Guards
                      We are making the following four recommendations to DOT:
Recommendations for
Executive Action      The Administrator of the National Highway Traffic Safety Administration
                      should recommend to the expert panel of the Model Minimum Uniform
                      Crash Criteria to update the Criteria to provide a standardized definition of
                      underride crashes and to include underride as a recommended data field.
                      (Recommendation 1)

                      The Administrator of the National Highway Traffic Safety Administration
                      should provide information to state and local police departments on how
                      to identify and record underride crashes. (Recommendation 2)

                      The Administrator of the Federal Motor Carrier Safety Administration
                      should revise Appendix G of the agency’s regulations to require that rear
                      guards are inspected during commercial vehicle annual inspections.
                      (Recommendation 3)

                      The Administrator of the National Highway Traffic Safety Administration
                      should conduct additional research on side underride guards to better
                      understand the overall effectiveness and cost associated with these
                      guards and, if warranted, develop standards for their implementation.
                      (Recommendation 4)


                      We provided a draft of this report to DOT for comment. In its written
Agency Comments       comments, reproduced in appendix II, DOT stated that it concurred with
                      our recommendations. DOT also provided technical comments, which we
                      incorporated as appropriate.


                      As agreed with your offices, unless you publicly announce the contents of
                      this report earlier, we plan no further distribution until 30 days from the
                      report date. At that time, we will send copies to the appropriate
                      congressional committees, the Secretary of Transportation, and other
                      interested parties. In addition, the report will be available at no charge on
                      the GAO website at http://www.gao.gov.




                      Page 33                                       GAO-19-264 Truck Underride Guards
If you or your staff have any questions about this report, please contact
me at (202) 512-2834 or flemings@gao.gov. Contact points for our
Offices of Congressional Relations and Public Affairs may be found on
the last page of this report. GAO staff who made key contributions to this
report are listed in appendix III.




Susan Fleming
Director, Physical Infrastructure




Page 34                                      GAO-19-264 Truck Underride Guards
Appendix I: Objectives, Scope, and
              Appendix I: Objectives, Scope, and
              Methodology



Methodology

              Our work for this report focused on truck underride crashes, and the U.S.
              Department of Transportation’s (DOT) efforts related to this issue. In
              particular, this report examines (1) the data DOT reports on underride
              crashes, and (2) the development and use of underride guard
              technologies in the U.S.

              For both objectives, we conducted a literature review to identify studies
              regarding truck safety, in general, and underride guards, in particular,
              published from 1970 through 2018. We conducted a search for relevant
              peer-reviewed articles, government reports, trade and industry articles,
              and think tank publications. Key terms included various combinations of
              “underride,” “crash,” “collision,” and “guard.” We included those studies
              that were methodologically sound and covered underride crash data,
              guard technologies, and benefits and costs relevant to our scope.
              Additionally, we interviewed and analyzed the perspectives of
              government officials from DOT, the National Highway Traffic Safety
              Administration (NHTSA), the Federal Motor Carrier Safety Administration
              (FMCSA), and the National Transportation Safety Board. We interviewed
              officials from foreign transportation agencies—Canada and the European
              Union—that were selected based on our review of literature identified
              above and recommendations from preliminary interviewees. We also
              interviewed a variety of relevant non-governmental organizations to gain
              their perspectives on topics related to underride crashes and guards.
              These organizations represent a variety of key players in their respective
              fields on underride crash-related topics. We grouped these entities into
              the following categories: (1) trailer manufacturers, (2) trucking industry
              organizations, (3) tractor-trailer fleets and related organizations, (4) traffic
              safety organizations, and (5) research organizations. We interviewed
              seven of the top eight trailer manufacturers in the United States, as
              identified by the Insurance Institute for Highway Safety. We requested an
              interview with Stoughton Trailers, but they declined to participate. The
              organizations we contacted as part of this work are listed at the end of
              this section. We also interviewed NHTSA officials and conducted semi-
              structured interviews with officials in five selected states, including
              officials in five state departments of transportation and five state and two
              local police departments to understand and identify limitations, if any, in
              how underride crash-related data are collected and analyzed. The results
              of these interviews are not generalizable to all states and localities;
              however, they offer examples of the types of experiences state DOTs and
              police have with underride crashes and inspections. We selected states
              based on several factors to identify states that were similar in highway
              traffic trends and large truck-related fatality rates, but collected underride
              crash data differently. Selection factors included highway vehicle miles


              Page 35                                         GAO-19-264 Truck Underride Guards
Appendix I: Objectives, Scope, and
Methodology




traveled per state, total underride crash fatalities by state in 2016 as
reported by NHTSA, and the presence of an underride crash data field on
each state’s crash report form. Based on these factors, we selected and
conducted interviews with state DOT and state police officials in
California, Illinois, Indiana, Pennsylvania, and Tennessee. We also
corresponded with officials from the Ohio DOT for clarification questions.
We interviewed local police departments in Chicago, Illinois and Terre
Haute, Indiana.

To identify the data DOT reports on truck underride crashes, we analyzed
existing DOT data on underride crashes and fatalities from 2008 through
2017, the 10 most recent years for which these data are available. We
reviewed DOT documentation for policies and procedures on data
collection and data reliability assessments for underride crash-related
data. NHTSA fatality data came from the Fatality Analysis Reporting
System (FARS). FARS is a census of all fatal traffic crashes in the United
States that provides uniformly coded, national data on police-reported
fatalities. We analyzed these data to determine the reported number of
fatalities involving underride crashes. To assess the reliability of the
FARS data, we reviewed relevant documentation and spoke with agency
officials about the data’s quality control procedures. We determined that
the data were sufficiently reliable for the purposes of this report,
specifically to provide a high-level overview of underride crash fatalities
within recent years. However, we did identify potential underreporting of
underride crashes and fatalities, as discussed in this report. We also
reviewed NHTSA’s annual Traffic Safety Facts reports—which use FARS
data—to determine the annual number of traffic and large truck crash
fatalities from 2008 to 2017, the 10 most recent years for which these
data are available. We reviewed state crash report forms from all 50
states and the District of Columbia to understand the variability of
underride crash-related data elements and how such variability could
affect DOT’s data collection and analysis efforts. We compared NHTSA’s
data collection efforts to federal internal control standards related to use
of quality information.

To describe the development and use of truck underride guard
technologies in the United States, we reviewed research and
documentation on underride guards. Primarily, we reviewed documents
relating to underride guards from NHTSA and FMCSA, as well as
information from traffic safety groups, trucking industry organizations,
research organizations, and selected foreign transportation agencies. We
reviewed NHTSA’s regulations requiring rear guards, FMCSA’s
regulations requiring commercial vehicle inspections, DOT’s


Page 36                                       GAO-19-264 Truck Underride Guards
                          Appendix I: Objectives, Scope, and
                          Methodology




                          documentation on underride guard technologies, and DOT data on
                          commercial vehicle inspections. To assess the reliability of DOT’s
                          commercial vehicle inspection data, we reviewed relevant documentation
                          and spoke with agency officials about the data’s quality control
                          procedures. We determined that the data were sufficiently reliable for the
                          purposes of this report, specifically to provide a high-level overview of
                          commercial vehicle inspections within recent years. We compared DOT’s
                          efforts to pertinent agency regulations on commercial vehicle inspections,
                          federal internal control standards related to use of quality information, and
                          a statement of federal principles on regulatory planning and review. We
                          spoke with relevant non-governmental organizations to obtain their
                          perspectives on the perceived benefits and costs of rear, side, and front
                          underride guards, and the potential factors that may influence the benefits
                          and costs.

                          We conducted this performance audit from January 2018 to March 2019
                          in accordance with generally accepted government auditing standards.
                          Those standards require that we plan and perform the audit to obtain
                          sufficient, appropriate evidence to provide a reasonable basis for our
                          findings and conclusions based on our audit objectives. We believe that
                          the evidence obtained provides a reasonable basis for our findings and
                          conclusions based on our audit objectives.


Organizations Contacted   We interviewed representatives from the following entities:

                          Federal Government Entities

                          •   U.S. Department of Transportation
                              •     National Highway Traffic Safety Administration (NHTSA)
                              •     National Institute for Safety Research (NHTSA’s data validation
                                    and training contractor)
                              •     Federal Motor Carrier Safety Administration
                          •   National Transportation Safety Board

                          State Government Entities

                          •   California Department of Transportation
                          •   California Highway Patrol
                          •   Illinois Department of Transportation



                          Page 37                                        GAO-19-264 Truck Underride Guards
Appendix I: Objectives, Scope, and
Methodology




•   Illinois State Police
•   Indiana Department of Transportation
•   Indiana State Police
•   Pennsylvania Department of Transportation
•   Pennsylvania State Police
•   Tennessee Department of Transportation
•   Tennessee Highway Patrol

Local Police Departments

•   Chicago, Illinois Police Department
•   Terre Haute, Indiana Police Department

Foreign Government Entities

•   European Commission for Growth—Internal Market, Industry,
    Entrepreneurship and SMEs
•   European Commission for Mobility and Transport
•   Transport Canada

Trailer Manufacturers

•   Great Dane Trailers
•   Hyundai Translead
•   Manac Inc.
•   Strick Trailers
•   Utility Trailer Manufacturing Company
•   Vanguard National Trailer Corp.
•   Wabash National

Trucking Industry Organizations

•   AirFlow Deflector
•   American Trucking Associations
•   Arconic




Page 38                                      GAO-19-264 Truck Underride Guards
Appendix I: Objectives, Scope, and
Methodology




•   Hydro
•   Motor and Equipment Manufacturers Association
•   Owner Operator Independent Drivers Association
•   Truck and Engine Manufacturers Association
•   Truck Trailer Manufacturers Association
•   Volvo

Tractor-Trailer Fleets and Related Organizations

•   Association for the Work Truck Industry
•   M&J Intermodal/Eagle Intermodal
•   National Association of Fleet Administrators
•   US Foods

Traffic Safety Organizations

•   Advocates for Highway and Auto Safety
•   AnnaLeah & Mary for Truck Safety
•   Commercial Vehicle Safety Alliance
•   Governors Highway Safety Association
•   Insurance Institute for Highway Safety
•   National Sheriffs’ Association
•   Property Casualty Insurers Association of America
•   Stopunderrides.org
•   Truck Safety Coalition

Research Organizations

•   Collision Safety Consulting
•   Friedman Research Corporation
•   Texas A&M Transportation Institute, Center for Transportation Safety
•   University of North Carolina, Gillings School of Global Public Health




Page 39                                       GAO-19-264 Truck Underride Guards
Appendix II: Comments from the Department
             Appendix II: Comments from the Department
             of Transportation



of Transportation




             Page 40                                     GAO-19-264 Truck Underride Guards
Appendix III: GAO Contact and Staff
                  Appendix III: GAO Contact and Staff
                  Acknowledgments



Acknowledgments

                  Susan Fleming, (202) 512-2834 or flemings@gao.gov.
GAO Contact
                  In addition to the contact named above, Sara Vermillion (Assistant
Staff             Director); Daniel Paepke (Analyst in Charge); Carl Barden; Jessica Du;
Acknowledgments   Mary Edgerton; Timothy Guinane; David Hooper; Gina Hoover; Madhav
                  Panwar; Joshua Parr; Malika Rice; Oliver Richard; Matthew Rosenberg;
                  Pamela Snedden; and Michelle Weathers made key contributions to this
                  report.




(102568)
                  Page 41                                    GAO-19-264 Truck Underride Guards
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