oversight

Transportation Infrastructure: Better Data Needed to Rate the Nation's Highway Conditions

Published by the Government Accountability Office on 1999-09-27.

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

                  United States General Accounting Office

GAO               Report to Congressional Committees




September 1999
                  TRANSPORTATION
                  INFRASTRUCTURE
                  Better Data Needed to
                  Rate the Nation’s
                  Highway Conditions




GAO/RCED-99-264
                   United States
GAO                General Accounting Office
                   Washington, D.C. 20548

                   Resources, Community, and
                   Economic Development Division

                   B-281731

                   September 27, 1999

                   The Honorable John H. Chafee
                   Chairman
                   The Honorable Max S. Baucus
                   Ranking Minority Member
                   Committee on Environment and Public Works
                   United States Senate

                   The Honorable Bud Shuster
                   Chairman
                   The Honorable James L. Oberstar
                   Ranking Democratic Member
                   Committee on Transportation and Infrastructure
                   House of Representatives

                   The International Roughness Index is used throughout the world to
                   measure whether travelers experience a rough or a smooth ride while
                   driving on a highway. The index is a quantitative measure of a vehicle’s
                   up-and-down movement while traveling. In the United States, the states
                   use specially equipped vehicles to collect data for the index and report the
                   data to the Department of Transportation (DOT). The Department uses the
                   index to describe the condition of pavement across the nation, to set a
                   performance goal for the quality of the nation’s highways, and to project
                   pavement investment needs through a computer model called the Highway
                   Economic Requirements System. The Secretary has delegated
                   responsibility for collecting data on pavement conditions to the Federal
                   Highway Administration (FHWA).

                   The Transportation Equity Act for the 21st Century (TEA-21) (P.L.
                   105-178) directed GAO to evaluate how the index is used and how reliable
                   the data are and report the results to the Congress no later than June 9,
                   2000. Accordingly, this report describes (1) the uses FHWA, the states, and
                   others make of the index to assess highway conditions, (2) the consistency
                   and accuracy of state-reported data on highway roughness, and (3) FHWA’s
                   efforts to improve the data across states.


                   The International Roughness Index is used widely for federal and state
Results in Brief   purposes, as well as for independent analyses. At the national level, where
                   the index is the only available statistic on pavement conditions, FHWA uses
                   it to assess changes in the overall condition of the nation’s highways and




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to forecast future highway investment needs. For example, in 1997, FHWA
projected that repairing deficiencies on the nation’s highways would cost
$70.3 billion annually. Actual expenditures for highways by all levels of
government in 1995 were about $29.2 billion, or about $41 billion less than
FHWA had projected as needed to repair the deficiencies. In addition, FHWA
uses the index to measure progress toward a goal for ride quality in its
strategic plan and publishes data from the index for use by the public. At
the state level, where other types of data on pavement conditions are
available, reliance on the index varies. While some states rely on it to
make highway maintenance decisions, others do not consider it an
important decision-making tool. The states that rely on the index use it to
project highway investment needs and report on pavement performance at
the state or district levels. In addition, some states use the index to set
standards for construction projects. Independent analysts have used the
data to compare pavement conditions across states and to develop “report
cards” of state performance.

Critics contend that state comparisons based on the index are flawed
because the pavement roughness data reported to FHWA by the states are
not consistent or accurate. These problems with consistency and accuracy
have occurred for two reasons. First, the states use different methods to
gather data and compute the results. The states differ in the devices they
use to measure the pavement, the part of the road they measure, and their
choice of an appropriate mathematical simulation. As a result,
state-to-state comparisons are not valid. Second, the type of
surface—asphalt or concrete—influences the results. Concrete roads may
produce rougher readings than asphalt roads, even if the concrete road is
of very high quality. Features such as joints between sections can
contribute to the roughness of concrete highways.

While FHWA has tried to improve the data, these efforts have not been
completely successful. The agency developed detailed guidelines for
collecting the data and asked the states to apply these guidelines before
reporting the data. However, FHWA accepts any data that the states submit,
even if they do not meet its data collection guidelines. Accordingly, we are
recommending that FHWA revise its data collection guidelines to limit the
technology and procedures the states may use in collecting International
Roughness Index data and work with the states to seek compliance with
these guidelines. Such action will help to ensure the reliability of the index
data that the Department uses for several critical activities, including the
estimation of the nation’s highway investment needs.




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             In 1993, FHWA adopted the International Roughness Index as a measure for
Background   the states to use in assessing and reporting highway conditions in the
             United States. FHWA viewed the index as an improvement over an earlier,
             more subjective method that permitted ride and visual evaluations of
             highways by state inspectors. In adopting the index, FHWA believed it
             would improve the reliability of national data on pavement conditions. In
             addition, the index was accepted worldwide and was used by foreign
             countries and the World Bank as a measure of pavement conditions. FHWA
             wanted the nation’s system of measuring pavement conditions to be
             consistent with international guidelines.

             The index is a quantitative measure of a vehicle’s up-and-down motion
             while the vehicle is traveling at a specific speed. Most states collect and
             measure the data with specially equipped vans, called profilers (see fig. 1).
             The vans can operate at highway speeds and can cost from $75,000 to
             $1,500,000.1 However, these costs are dropping as the costs of computers
             and sensors decline. A profiler has sensors attached underneath the van
             that quickly gauge the surface, or “profile,” of the road as the van travels
             at normal speeds in traffic. The vehicle typically has a computer and three
             types of sensing equipment: a height sensor,2 an acceleration sensor, and a
             speed/distance device connected to the profiler’s speedometer or to a
             wheel. Height sensors measure the up-and-down movement of the van,
             acceleration sensors detect changes in the speed of the van’s up-and-down
             movement, and speed/distance sensors measure how fast the van is
             traveling and how far it has traveled. All of these measurements are
             needed to compute an International Roughness Index statistic. On a
             smooth road, the up-and-down movements are small and the road’s index
             is low, but on a rough road with large cracks and potholes, up-and-down
             movements are more noticeable and the index is higher. The index is
             measured in inches per mile; smooth roads have an index of up to 60
             inches per mile, while rough roads have an index of about 170 inches per
             mile or greater.




             1
              Most profilers cost under $200,000. The more expensive devices cited here often perform additional
             functions, such as videotaping and measuring the depth of ruts.
             2
              Height sensors use a wide variety of technologies, including laser, infrared, optical, and ultrasonic
             types.



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Figure 1: Profiler Vehicle




                                                                                                       Engineering Information

                                                                                                       Number of units owned by Pennsylvania
                                                                                                       Department of Transportation — 3

                                                                                                       Months of operation — March to November

Height sensors mounted in the front bumper of this Pennsylvania Department of Transportation road      Personnel needed for operation — 2
profiler send pavement data to an onboard computer for calculating the International Roughness         (operator and driver)
Index.
                                                                                                       Number of test miles measured in
                                                                                                       1997 — 14,744

                                                  Source: Pennsylvania Department of Transportation.



                                                  DOT  uses International Roughness Index data in reports describing the
DOT, the States, and                              overall condition of the nation’s roads and forecasting future highway
Others Have Various                               investment needs. FHWA publishes the data annually in its publication,
Uses for the Index                                Highway Statistics, and uses the data to support conclusions in the
                                                  Department’s Conditions and Performance Report, a biennial report to
                                                  congressional authorizing committees on the state of the nation’s roads.
                                                  (App. I contains an example of the roughness data published in FHWA’s
                                                  Highway Statistics.) The 1997 Conditions and Performance Report
                                                  contains estimates of the nation’s highway investment needs for the next
                                                  20 years. For example, in 1997, FHWA projected that repairing deficiencies
                                                  on the nation’s highways, when the repairs were economically justifiable,
                                                  would cost $70.3 billion annually. In comparison, all levels of government
                                                  spent $29.2 billion for highways in 1995—a shortfall of about $41 billion.
                                                  FHWA’s computer model, using roughness index and other data, projects
                                                  this needs estimate.3




                                                  3
                                                   FHWA also projects pavement investment needs with another computer model, known as the Analytic
                                                  Process model.



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FHWA also uses the data as a performance indicator for the nation’s
highways. Under the Government Performance and Results Act of 1993,
FHWA and the Department use the data to set a goal for ride quality in their
performance plans. The performance plans call for 93 percent of the
National Highway System4 to have an index of below 170 inches per mile
by 2008. Using 1997 data (the most recent data available), FHWA reported in
1999 that 91.7 percent of the National Highway System had already
achieved this goal, and therefore officials believe the goal is achievable.
However, FHWA noted that since the index measures only pavement
roughness, other measurements of pavement distress would be needed to
fully assess the overall condition of the nation’s highways.

The states we reviewed vary in the extent to which they rely on the index
to make maintenance decisions or manage their construction schedules.
For example, three of the seven states we reviewed—Ohio, Pennsylvania,
and South Dakota—believe the index is helpful in managing the condition
of their pavement and use the data in determining their pavement
investment needs. These states use the data as an indicator of pavement
performance statewide or at the highway district level. Four of the seven
states—Georgia, Pennsylvania, South Dakota, and Texas—currently use or
plan to use the index as a construction specification for new pavement
construction. For example, in Georgia, contractors must construct new
highways with an index reading below 47 inches per mile. Georgia
Department of Transportation officials claim that this requirement
explains the low roughness of their roads. These officials also stated that
contractors in Georgia rarely deliver new pavement that fails to meet this
requirement. On the other hand, New York does not use the index for any
state purpose; it collects the data only to fulfill FHWA’s requirement that the
states report index measurements.

Outside analysts also use roughness index data for studies of pavement
conditions and performance. Nonprofit organizations and academic
institutions occasionally publish “report cards” comparing pavement
conditions among the states. For example, the Surface Transportation
Policy Project issued reports in 1997 and 1998 based, in part, on FHWA’s
index data. (App. II contains an example of a Surface Transportation
Policy Project report card.) These reports ranked the states on the
condition of their roads and estimated how much the condition of the
roads cost drivers in repair bills. The Surface Transportation Policy
Project report uses FHWA’s data to categorize a state’s roads as good, fair,

4
 The National Highway System is a federally designated portion of the nation’s roads consisting mainly
of interstate highways and other arterial roads.



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                     mediocre, or poor. Similarly, the Center for Interdisciplinary
                     Transportation Studies at the University of North Carolina-Charlotte has
                     issued annual reports since 1993 ranking state transportation departments
                     on the cost-effectiveness of their expenditures. The Center’s reports use
                     index data and other indicators, such as how much a state highway
                     department spends for administration, to determine how effectively a state
                     spends its transportation dollars. These reports and others like them can
                     be controversial, especially among those states that do not appear high in
                     the reports’ rankings. For example, officials from the Maryland State
                     Highway Administration expressed concern over the controversy
                     generated by one such report that the officials felt erroneously portrayed
                     the condition of their highway system. Similar controversies arose in
                     Illinois and Iowa. These reports contrast with those that FHWA publishes.
                     FHWA’s Highway Statistics contains an annual listing of state index data but
                     makes no attempt to rank the states according to the condition of their
                     roads. FHWA officials noted that Highway Statistics includes a notice that
                     users need to account for variability in the index data reported by the
                     states. The notice explains that sources of variability include differences in
                     the type of pavement material, in measuring equipment, and in
                     measurement protocols.


                     The states’ roughness index data are not comparable because the states
Differing State      differ in the devices and procedures they use to measure the roughness of
Procedures Produce   their highways, as well as in the mathematical simulation they use to
Inconsistent Data    calculate the index. Any one of these factors can bias the results,
                     producing inaccurate and inconsistent data. However, the cumulative
                     effect of these differences among states is unknown—some state practices
                     tend to reduce values in the data, while others overstate the values. These
                     known sources of variability reduce the accuracy of the data disseminated
                     by FHWA and limit the comparability of the data from state to state.
                     Furthermore, different types of pavement—concrete and asphalt—may
                     differ in roughness, according to state highway officials. As a result, the
                     states with more concrete pavement may have higher index readings than
                     the states that primarily use asphalt.

                     The states use laser, optical, infrared, and ultrasonic profilers to assess a
                     road’s roughness and determine its index. According to a 1998 survey by
                     the Florida Department of Transportation to which 38 states responded, 28
                     states used laser devices, 9 used ultrasonic devices, 4 used infrared
                     devices, and 2 used optical devices.5 The technology used by the profiler

                     5
                      Some states collect index data with more than one type of height sensor.



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can affect the measurement of roughness. Laser, optical, and infrared
devices all measure roughness by emitting beams of light and measuring
the distance between the vehicle body and the road. Ultrasonic sensors
measure roughness by emitting a sound wave and measuring how long it
takes for the sound wave to travel back to the sensor to compute the
distance between the vehicle and the road. Ultrasonic sensors do not
sample as much of the pavement as other types of sensors. This limits
their ability to measure roughness reliably. For example, a 1998 study for
the Florida Department of Transportation showed that a low-cost
ultrasonic sensor still in use by some states produced measurements about
25 percent higher than profilers using laser technology. The results were
particularly dramatic on certain rough surfaces. States switching from
ultrasonic sensors to laser sensors could show a marked “improvement”
in their roads, even if pavement conditions stayed exactly the same. None
of the states we contacted were using ultrasonic sensors, and four of the
seven had replaced old ultrasonic sensors with other types.

The states also differ in their procedures for operating profiler vans, and
these differences can affect the data. For example, most states use two
technicians to measure roughness. A 1999 study by the University of
Michigan Transportation Research Institute recommended the use of at
least two people, one to drive and the other to take the readings.6 The
driver can then focus on the van’s lane position, speed, and safety while
the operator finds landmarks, triggers the system, and conducts quality
control steps during measurements. However, according to a Georgia
Department of Transportation official, Georgia uses only one person to
perform both functions. Of the other states we contacted, Illinois, Ohio,
Pennsylvania, South Dakota, and Texas use two people to gather the data.
New York officials could not tell us how many people take the readings in
their state because private contractors perform that task. FHWA officials
said a definitive study has not been done on the effect of a profiler’s crew
size on roughness index data, but they thought a larger crew might be a
good safety factor.

The location of the profiler equipment can also affect the measurement of
roughness. Some states measure a highway’s roughness over the path of
the right wheel, while other states measure the left wheel path or take
readings over the paths of both wheels and average the two results.
Generally the right wheel path is the roughest part of the highway lane,
and thus readings are higher from the right wheel than from the left wheel

6
 This study also addresses other data quality issues, such as standardizing the profiler’s design and
other system operating practices.



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or the average of both wheels. FHWA recommends that the states collect
data over the right wheel but allows them to average measurements
collected over both wheels.7 A Florida Department of Transportation study
found that 4 states gathered data over the left wheel, 13 gathered data over
the right wheel, and 14 averaged the measurements gathered over both
wheels. In addition, under FHWA’s guidelines, the states are to exclude
readings taken when their profilers cross bridges and railroad tracks.
However, some states include these readings in their data. For example,
Illinois, which has more rail-highway crossings than any other state except
Texas, includes readings over bridges and railroad crossings in its data.

FHWA’s guidelines contain specific procedures for calculating a roughness
index from the raw data collected by the profiler. The guidelines call for
the states to use a method known as a quarter-car simulation.8 However
some states have not always used this method. For example, two of the
states we contacted, Georgia and Ohio, computed their index using a
method known as a half-car simulation.9 A 1998 University of Michigan
report compared the two methods and found that half-car measurements
were 11 percent smoother than quarter-car measurements on the same
roads. In addition, before 1997, Texas gathered data for a different
pavement condition statistic—the Pavement Suitability Index—converted
it to an International Roughness Index value, and reported the converted
statistic to FHWA. FHWA found that this approach produced unrealistic
measurements of roughness for certain pavements. For example, Texas
Department of Transportation officials stated that the conversion
produced index measurements of zero (a glass highway) for about
40 percent of the state’s highways. In response to these results and FHWA’s
concerns, Texas changed its methods and began to measure the
International Roughness Index directly as of 1997.

Finally, the type of pavement can also affect measurements of roughness.
Officials from Georgia, Illinois, and New York all stated that concrete
pavements generally have higher index readings than asphalt pavements,
even when the two types of pavements are in comparable physical
condition. For example, a New York official said that past measurements
had shown new concrete pavement with index values 30 inches per mile

7
 In early 1999, FHWA announced it would accept index data averaged from the left and right wheels, as
authorized by new protocols approved by the American Association of State Highway and
Transportation Officials. These protocols differ somewhat from FHWA’s current guidelines.
8
 The quarter-car simulation involves modeling the movement of one corner of a passenger car’s
suspension over the road being profiled.
9
 The half-car simulation involves modeling the movement of half a passenger car’s suspension over the
road being profiled.



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                         rougher than new asphalt pavement. This difference may have occurred, in
                         part, because some concrete pavement, unlike asphalt, has joints between
                         the concrete sections, and each concrete section has a slight natural curve
                         in it. FHWA does not distinguish between pavement types when it publishes
                         its data, so direct comparisons cannot be made between states that mainly
                         use asphalt and states that mainly use concrete. FHWA officials noted that
                         pavement contractors have developed ways of building concrete highways
                         that can match asphalt highways in terms of roughness.


                         FHWA  has developed guidelines for the states to use in collecting, analyzing,
FHWA Has Not             and reporting data on pavement roughness. However, some elements of
Required the States to   these guidelines allow for inconsistencies in the way the states collect the
Comply With Its          data. In addition, while FHWA has emphasized the importance of these
                         guidelines, it does not require the states to follow them. FHWA instead relies
Guidelines for           on persuasion to get the states to collect data as specified in the
Collecting               guidelines.
International            In 1993, FHWA developed guidelines on measuring roughness and provided
Roughness Index Data     the states with detailed instructions for collecting and reporting the data.
                         FHWA issued its guidelines as an appendix to its Highway Performance
                         Monitoring System field manual. This appendix provides detailed
                         instructions on measuring roughness—where on a roadway the state
                         agencies should measure the pavement, what types of measuring devices
                         are acceptable, how the index is computed, and other technical issues.
                         The appendix also instructs the states to exclude roughness
                         measurements taken at bridges, railroad tracks, and other obstacles
                         designed as part of the roadway. At the same time, the guidelines allow for
                         inconsistencies in collecting the data. For example, the states are allowed
                         to use mechanical roughness meters10 instead of the more accurate
                         profilers. Also, under the guidelines, the states are allowed to measure
                         roughness in the left wheel path if measuring the preferred right wheel
                         path is not practical. However, FHWA’s instructions do not otherwise
                         address deviations from the guidelines.

                         FHWA expressed its desire for consistency in the states’ application of its
                         guidelines in 1994, when it directed its field staff to review the equipment
                         the states used to collect roughness data, the frequency with which they
                         collected data, and the reasonableness of the data they reported. FHWA

                         10
                           Mechanical roughness meters would collect index data by measuring the response of a mechanical
                         device—like a fifth tire riding behind a car—in contact with the roadway as the device traveled on a
                         road. In contrast, the profilers most commonly used today rely on sensors, such as lasers, that are not
                         in contact with the road.



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field office staff at one of the states we visited found large-scale errors in
their state’s reports of roughness data. The state subsequently revised its
data collection process to satisfy FHWA.

When the states deviated from FHWA’s guidelines, they generally had an
engineering reason for doing so. For example, Georgia and Ohio preferred
measurements based on half-car simulations rather than quarter-car
simulations because they had been collecting pavement roughness data
before FHWA introduced its guidelines and the data from half-car
simulations better matched their data from prior years. Pennsylvania and
South Dakota left the measurements taken over bridges and railroad grade
crossings in their data because they considered the information potentially
useful in identifying trouble spots.

In general, FHWA has not strictly imposed its data collection guidelines on
the states, and it accepts the data the states submit. FHWA has legal
authority to impose and enforce requirements for accurate data. FHWA
officials stated that the sanction for noncompliance could be for the
agency to withhold planning and research funds. However, officials noted
that the states use these funds to pay for many other data elements they
report for FHWA’s Highway Performance Monitoring System field manual,
as well as for other planning and research activities, including
metropolitan planning, statewide planning, and clean air requirements.
FHWA officials also told us that persuasion was their preferred tool for
encouraging the states to report roughness index data as specified in the
agency’s guidelines.

New protocols on measuring pavement roughness issued in early 1999 by
the American Association of State Highway and Transportation Officials
(AASHTO) could help address the problem of inconsistencies in the states’
application of FHWA’s guidelines. FHWA supported the development of
AASHTO’s protocols,11 believing they would help standardize state data
collection practices. FHWA officials told us they plan to issue a new
Highway Performance Monitoring System field manual by the end of 1999
that incorporates AASHTO’s new protocols, called provisional standards. In
addition, to obtain closer compliance with its reporting requirements,


11
 AASHTO’s protocols differ from FHWA’s guidelines in that they call for the states to measure
pavement roughness in both the right and left wheel paths and average the measurement to calculate a
roughness index statistic. While FHWA recently agreed to accept data averaged according to
AASHTO’s protocols, FHWA’s current guidelines call for taking measurements from only one wheel
path, preferably the right wheel path. Furthermore, AASHTO’s protocols do not address what types of
profilers the states should use to collect data, whether the states should exclude data collected over
bridges and railroad crossings, or how many technicians the states should use to collect index data.



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                  FHWA will include revised instructions on gathering roughness data in the
                  appendix to its new field manual.

                  Finally, recognizing the importance of consistent roughness data as a
                  performance indicator for FHWA’s strategic planning process and as a
                  factor in estimating highway investment requirements for the Congress,
                  FHWA officials said they plan to examine several issues related to collecting
                  more consistent roughness data. Specifically, FHWA plans to

              •   evaluate the effects of different data collection and analysis protocols on
                  the roughness data,

              •   assess current practices to identify where changes could significantly
                  improve roughness data, and

              •   work with its field offices and the state highway agencies to implement
                  changes that would make roughness data more consistent.


                  The International Roughness Index is a more consistent tool for measuring
Conclusions       pavement conditions than the subjective system FHWA previously used.
                  However, the data on pavement roughness that FHWA receives from the
                  states need to be more consistent and accurate. Differences in the states’
                  data collection methods and the resulting lack of comparable data become
                  important when FHWA aggregates the data to the national level, such as
                  when the data are used in the Department’s model for projecting the
                  nation’s highway investment needs. Unreliable statistics result from
                  aggregating data that are not comparable. For example, FHWA will not be
                  able to determine with confidence that it has met the Department’s
                  performance goal for pavement condition set under the Results Act—that
                  93 percent of the National Highway System have an index below 170
                  inches per mile by 2008. Without accurate data on pavement roughness,
                  FHWA cannot reliably assess the current condition of the highways relative
                  to the goal or determine whether progress is being made toward the goal.
                  In addition, meaningful comparisons among the states cannot be drawn
                  using the data because the states use different procedures and calculation
                  methods. While FHWA has given the states wide latitude in how they report
                  pavement roughness data, FHWA also has the authority to require that they
                  use accurate equipment and consistent techniques to collect the data.




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                     To enable the Federal Highway Administration to reliably report on the
Recommendations to   condition of the nation’s highways and accurately estimate the nation’s
the Secretary of     highway investment needs, we recommend that the Secretary of
Transportation       Transportation direct the Administrator, Federal Highway Administration,
                     to revise the agency’s guidelines to exclude profiling technologies known
                     to produce significant errors and achieve consistency with the American
                     Association of State Highway and Transportation Officials’ protocols. We
                     further recommend that the Administrator work with the states to
                     implement the revised guidelines.


                     We provided a copy of a draft of this report to the Department of
Agency Comments      Transportation for review and comment. We discussed the draft report
and Our Response     with Department officials, including the Federal Highway Administration’s
                     Director, Office of Highway Policy Information, and Acting Director,
                     Office of Pavement Technology. FHWA generally agreed with the findings
                     and our conclusion that the roughness data reported by the states could be
                     more consistent. However, FHWA disagreed with part of the
                     recommendation in our draft report, which said that FHWA should direct
                     the states to comply with its own and AASHTO’s guidelines on reporting
                     data. FHWA believed that it could obtain more consistent roughness index
                     data by working cooperatively with the states rather than by requiring
                     them to comply with a federal mandate. According to FHWA, such a
                     mandate was unwarranted. FHWA further stated that because the Congress
                     in the National Highway System Designation Act of 1995 overturned earlier
                     legislation that mandated state Pavement Management System
                     requirements, FHWA did not believe it was appropriate to impose criteria
                     for measuring roughness. FHWA believes it has worked effectively with the
                     states to obtain better roughness data and that the states have already
                     made great strides in improving their collection and reporting of the data.

                     FHWA also noted that it has planned several actions to obtain more
                     consistent roughness data from the states. First, it said it plans to adopt
                     AASHTO’s recently developed roughness standards as its own. FHWA believes
                     that these new standards will substantially address our concern about the
                     quality of the data. In addition, to obtain closer compliance with its
                     reporting requirements, FHWA said it will include revised instructions on
                     gathering roughness data in the appendix to its new Highway Performance
                     Monitoring System field manual. This appendix contains the guidelines
                     that states use. Finally, FHWA said it plans to evaluate the effects of
                     different data collection and analysis protocols on the roughness data,
                     assess current practices to identify where changes could significantly



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              improve the data, and work with its field offices and the state highway
              agencies to implement changes that will improve the consistency of
              reported roughness data.

              FHWA  believes that adopting AASHTO’s protocols, along with taking the
              actions it has planned, will address our concerns without imposing a
              federal mandate. We are encouraged by FHWA’s recently stated
              commitment to work with the states on these issues and agree that a
              federal mandate may not be necessary. Nevertheless, we believe that
              following through on plans such as this is often just as difficult as
              developing them. Accordingly, we have revised our recommendation to
              reflect FHWA’s new plan and this continuing need.

              FHWA made a number of additional technical comments on the report,
              which we incorporated as appropriate.


              We contacted FHWA and state transportation department officials to
Scope and     determine how they use International Roughness Index data. We
Methodology   examined state and federal reports based on these data and
              documentation concerning FHWA’s Highway Performance Monitoring
              System database and the related models for projecting future highway
              investment needs. Furthermore, to assess independent uses of roughness
              index data, we reviewed reports by the Surface Transportation Policy
              Project and the Center for Interdisciplinary Transportation Studies at the
              University of North Carolina-Charlotte. To obtain information about the
              reliability of the data, we interviewed FHWA and state transportation
              department officials about data collection practices and reliability. In
              particular, we interviewed state transportation department officials from
              seven states about their experience and concerns with the reliability of the
              roughness data. The seven states—Georgia, Illinois, New York, Ohio,
              Pennsylvania, South Dakota, and Texas—were selected to give us a broad
              cross section of opinions about the reliability and collection of the data.
              We also spoke with officials from Maryland about applications of the data.
              In addition, we interviewed experts in the field of pavement monitoring
              from the University of Michigan, the University of North
              Carolina-Charlotte, and a profiler manufacturer. We also analyzed
              pavement data from the Highway Performance Monitoring System
              database and reviewed reports on the reliability of roughness index data
              that were presented before the Road Profiler Users Group and the
              Transportation Research Board. We performed our review from




              Page 13                       GAO/RCED-99-264 International Roughness Index Data
B-281731




August 1998 through September 1999 in accordance with generally
accepted government auditing standards.


We will make copies of this report available to cognizant congressional
committees; the Honorable Rodney E. Slater, Secretary of Transportation,
the Honorable Kenneth R. Wykle, Administrator, Federal Highway
Administration; and other interested parties. We will make copies
available to others on request. Please call me at (202) 512-2834 if you or
your staff have any questions. Major contributors to this report were
Richard Calhoon, Joseph Christoff, Robert Ciszewski, and Raymond
Sendejas. Sincerely yours,




Phyllis F. Scheinberg
Associate Director,
  Transportation Issues




Page 14                       GAO/RCED-99-264 International Roughness Index Data
Page 15   GAO/RCED-99-264 International Roughness Index Data
Contents



Letter                                                                                               1


Appendix I                                                                                          18

Pavement Data
Published by the
Federal Highway
Administration
Appendix II                                                                                         20

Pavement Data
Published by the
Surface
Transportation Policy
Project
Figure                  Figure 1: Profiler Vehicle                                                   4




                        Abbreviations

                        AASHTO      American Association of State Highway and Transportation
                                        Officials
                        DOT         Department of Transportation
                        FHWA        Federal Highway Administration
                        TEA-21      Transportation Equity Act for the 21st Century


                        Page 16                      GAO/RCED-99-264 International Roughness Index Data
Page 17   GAO/RCED-99-264 International Roughness Index Data
Appendix I

Pavement Data Published by the Federal
Highway Administration




              Page 18     GAO/RCED-99-264 International Roughness Index Data
Appendix I
Pavement Data Published by the Federal
Highway Administration




Note: In this Federal Highway Administration table on the roughness of rural pavement, the states
are listed alphabetically.

Source: Highway Statistics 1997, Federal Highway Administration.




Page 19                                 GAO/RCED-99-264 International Roughness Index Data
Appendix II

Pavement Data Published by the Surface
Transportation Policy Project




              Note: In this Surface Transportation Policy Project chart, the states are listed by the percentage of
              pavement not in good condition.

              Source: Potholes & Politics 1998, Surface Transportation Policy Project.




(348119)      Page 20                                   GAO/RCED-99-264 International Roughness Index Data
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