Transportation Infrastructure: Better Data Needed to Rate the Nation's
Highway Conditions (Letter Report, 09/27/1999, GAO/RCED-99-264).

Pursuant to a legislative requirement, GAO provided information on
federal and state efforts to assess the conditions of the nation's
highways, focusing on: (1) the uses the Federal Highway Administration
(FHwA), the states, and others make of the International Roughness 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.

GAO noted that: (1) the International Roughness Index is used widely for
federal and state purposes, as well as for independent analyses; (2) 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 to forecast future highway
investment needs; (3) 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; (4) 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; (5) at the state level, where other types of data on
pavement conditions are available, reliance on the index varies; (6)
while some states rely on it to make highway maintenance decisions,
others do not consider it an important decision-making tool; (7) 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; (8)
in addition, some states use the index to set standards for construction
projects; (9) independent analysts have used the data to compare
pavement conditions across states and to develop scorecards of state
performance; (10) 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; (11) these problems with
consistency and accuracy have occurred for two reasons: (a) the states
use different methods to gather data and compute 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; and (b) 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; (12) features
such as joints between sections can contribute to the roughness of
concrete highways; (13) while FHwA has tried to improve the data, these
efforts have not been completely successful; and (14) the agency
developed detailed guidelines for collecting the data and asked the
states to apply these guidelines before reporting the data.

--------------------------- Indexing Terms -----------------------------

 REPORTNUM:  RCED-99-264
     TITLE:  Transportation Infrastructure: Better Data Needed to Rate
	     the Nation's Highway Conditions
      DATE:  09/27/1999
   SUBJECT:  Highway research
	     Federal aid for highways
	     Highway planning
	     Data integrity
	     Public roads or highways
	     Statistical data
	     Federal/state relations
	     Evaluation methods
	     Comparative analysis
	     Performance measures
IDENTIFIER:  FHwA Highway Performance Monitoring System
	     National Highway System
	     DOT Highway Economic Requirements System
	     International Roughness Index

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    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 GAO                 United States
    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. Results in Brief    The
    International Roughness Index is used widely for federal and state
    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 Page 1
    GAO/RCED-99-264 International Roughness Index Data B-281731 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. Page 2
    GAO/RCED-99-264 International Roughness Index Data B-281731
    Background    In 1993, FHWA adopted the International Roughness
    Index as a measure for 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.
    1Most profilers cost under $200,000. The more expensive devices
    cited here often perform additional functions, such as videotaping
    and measuring the depth of ruts. 2Height sensors use a wide
    variety of technologies, including laser, infrared, optical, and
    ultrasonic types. Page 3
    GAO/RCED-99-264 International Roughness Index Data B-281731 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, the States, and
    DOT uses International Roughness Index data in reports describing
    the Others Have Various                                overall
    condition of the nation's roads and forecasting future highway
    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 3FHWA also projects pavement
    investment needs with another computer model, known as the
    Analytic Process model. Page 4
    GAO/RCED-99-264 International Roughness Index Data B-281731 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, 4The National Highway
    System is a federally designated portion of the nation's roads
    consisting mainly of interstate highways and other arterial roads.
    Page 5                                    GAO/RCED-99-264
    International Roughness Index Data B-281731 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. Differing State       The states' roughness
    index data are not comparable because the states Procedures
    Produce    differ in the devices and procedures they use to
    measure the roughness of 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 5Some states collect index data
    with more than one type of height sensor. Page 6
    GAO/RCED-99-264 International Roughness Index Data B-281731 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 6This study also addresses other
    data quality issues, such as standardizing the profiler's design
    and other system operating practices. Page 7
    GAO/RCED-99-264 International Roughness Index Data B-281731 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 7In 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. 8The quarter-car simulation involves modeling the
    movement of one corner of a passenger car's suspension over the
    road being profiled. 9The half-car simulation involves modeling
    the movement of half a passenger car's suspension over the road
    being profiled. Page 8
    GAO/RCED-99-264 International Roughness Index Data B-281731
    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 Not                   FHWA has developed guidelines for
    the states to use in collecting, analyzing, Required the States to
    and reporting data on pavement roughness. However, some elements
    of 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 for                 guidelines, it does not require the
    states to follow them. FHWA instead relies on persuasion to get
    the states to collect data as specified in the Collecting
    guidelines. International Roughness Index Data In 1993, FHWA
    developed guidelines on measuring roughness and provided 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 10Mechanical 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. Page 9                                    GAO/RCED-
    99-264 International Roughness Index Data B-281731 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, 11AASHTO'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. Page 10
    GAO/RCED-99-264 International Roughness Index Data B-281731 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. Conclusions      The International Roughness
    Index is a more consistent tool for measuring 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. Page 11
    GAO/RCED-99-264 International Roughness Index Data B-281731
    Recommendations to    To enable the Federal Highway Administration
    to reliably report on the the Secretary of      condition of the
    nation's highways and accurately estimate the nation's 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. Agency Comments       We provided a copy
    of a draft of this report to the Department of and Our Response
    Transportation for review and comment. We discussed the draft
    report 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 Page 12                         GAO/RCED-99-264
    International Roughness Index Data B-281731 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.
    Scope and      We contacted FHWA and state transportation
    department officials to Methodology    determine how they use
    International Roughness Index data. We 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 Ordering
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