Highway Infrastructure: Interstate Physical Conditions Have Improved, but Congestion and Other Pressures Continue
Published: 2002-05-31T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: Federal spending on Interstate highways has contributed to changes in residential and business land-use patterns. In 1991, GAO raised concerns about the condition of Interstate highways and rising levels of congestion. The original purposes for the Interstate system were to provide for efficient long-distance travel, support defense, and connect metropolitan and industrial areas. Today, the most important role that the Interstates perform, other than supporting safe travel, is moving freight traffic across their states. The federal government provides funding for, and oversight of, the Interstate system while the states do most of the maintaining and planning for the future of the system. Combined federal and state spending on the Interstate System increased from $13.0 billion in 1992 to 16.2 billion in 2000.
section_title: What GAO Found
paragraphs: States are required to pay ten percent of the cost of an Interstate project; however, GAO found that the average nonfederal share of urban Interstate projects was 15 percent and 11 percent for rural projects. Interstate highways are in better physical condition and are safer than other classes of roads, although they are generally more congested. The states expect that increased traffic, the aging of the infrastructure, and funding constraints will affect their ability to maintain physical and safety conditions of the Interstate Systems and to alleviate congestion, but the costs to address the factors pressuring their Interstates were difficult to determine.

section_title: Letter
paragraphs: The Interstate Highway System, begun nearly a half century ago, has  become central to transportation in the United States. Federal officials  consider the Interstate Highway System the backbone of the nation’s  transportation system—connecting people with work, school, community  services, marketplaces, and each other, while providing a greater level of  safety than other roads. Federal spending on Interstate highways has also  contributed to changes in residential and business land-use patterns. From  1954 through 2001, the federal government has invested over $370 billion  in Interstate highways—nearly half of all federal highway apportionments  during this period.
In 1991, the Intermodal Surface Transportation Efficiency Act provided  funding for the completion of the Interstate Highway System.   Since that  time, the federal government and the states have focused primarily on  preserving and enhancing the capacity of the existing system. With age and  constant use, the system’s roads and bridges have required significant  levels of maintenance. Moreover, 24 percent of all car and truck travel  occurs on the Interstate System, contributing to growing levels of  congestion. In 1991, we raised concerns about the condition of Interstate  highways and the rising levels of congestion. Now, as Congress begins to  plan the next reauthorization of federal highway programs, it is appropriate  to examine the Interstate Highway System again.
Concerned about the condition of Interstate highways and bridges now and  into the future, you asked us to determine (1) how the role of the Interstate  Highway System has changed over time; (2) the roles of the federal and  state governments in managing and funding the Interstate System; (3) the  financial resources that states and the federal government have devoted to  the system; (4) how physical conditions, safety, and congestion of the  Interstate System have changed and how they compare to other classes of  roads; and (5) the factors that could affect future Interstate conditions and  the cost of addressing these factors.
To provide you with information addressing your concerns about the  Interstate Highway System, we conducted a nationwide mail survey of all  50 states, the District of Columbia, and Puerto Rico (referred to in this  report as states). We received responses from all 52 states. Our survey  focused on state officials’ views of the Interstate Highway System’s role in  their states’ transportation system, including changes in their roles over the  past 20 years. The survey also asked state officials for their views of the  Interstate System in 10 years and their perceptions of the current condition  of the system’s infrastructure, safety, and congestion. A summary of  responses to the survey appears in appendix II of this report. We also  visited five states—Arizona, Florida, Missouri, North Dakota, and  Pennsylvania—to obtain more detailed information on their Interstate  Systems and their plans for managing them. We also   reviewed the Interstate Highway System’s history and obtained data on  how it is currently used;   interviewed Federal Highway Administration (FHWA) officials at  headquarters and division (state) offices and Department of Defense  (DOD) officials;   obtained information from FHWA on funding for the system; and  obtained information from the U.S. Department of Transportation  (DOT) on pavement conditions, bridge conditions, safety conditions,  and congestion levels.
We did not review the impact of federal funding through the federal aid  highway program on states’ patterns or levels of investment in their  Interstate and other roads and bridges. (See app. I for a more detailed  discussion of our methodology.)
subsections: section_title: Background
paragraphs: The Federal-Aid Highway Act of 1944 established the Interstate Highway  System but did not provide specific funding for construction. In the  Federal-Aid Highway Act of 1956, Congress declared that the completion of  a “National System of Interstate and Defense Highways” was essential to  the national interest. The act called for new system design standards, began  an accelerated construction program, established a new method for  apportioning funds among states, and set the federal government’s cost  share for Interstate construction projects at 90 percent. At the same time,  the Highway Revenue Act of 1956 introduced a dedicated source for federal  highway expenditures, providing that revenue from certain federal motor  fuel and other motor vehicle related taxes be credited to the Highway Trust  Fund. The federal government, from 1954 through 2001, invested over $370  billion on Interstates through apportionments to the states, more than on  any other class of road. Today, FHWA, within DOT, administers a variety of  federal highway programs supported by the trust fund—collectively  referred to as the Federal-Aid Highway Program.
The Interstate Highway System, as it came to be known, has particular  design characteristics. Its roads are generally divided highways with at  least four lanes of traffic and wide shoulders. The Interstate avoids  intersections by having other roads pass over or under it, and it has access  control—that is, vehicles generally join or leave the flow of traffic by a  limited number of access or exit ramps. (See fig. 2.) Certain characteristics  were meant to facilitate military movement, such as the requirement for 16  feet of clearance under bridges that pass over Interstate highways. A  distinctive red, white, and blue shield denotes Interstate highways.
The Interstate Highway System, as of 2000, extended over 46,000 miles in  length and 209,655 lane miles. In 1991, Congress provided final funding for  the completion of the Interstate System. From 1990 through 2000,  Interstate mileage grew by about 3.1 percent, or 1,405 miles in length, or  11,491 lane miles during the decade. Growth occurred primarily in urban  areas. Overall, urban mileage climbed by 1,885 miles, or 16.2 percent,  during this period, while rural Interstate mileage declined by 480 miles, or  1.4 percent. (See fig. 3.) Some of the urban mileage gain occurred as new  road mileage expanded the system. The rest occurred as urban boundaries  grew to take in Interstate highway miles that were originally in rural areas.
According to FHWA, Interstate highways are a principal part of an overall  network of roads throughout the nation. The Interstate System composes  29 percent of the estimated 161,000-mile National Highway System (NHS)  designated by Congress in 1995. The NHS also includes other arterial roads  of national interest. The entire Interstate Highway System is also part of the  Strategic Highway Network (STRAHNET), an approximately 61,000-mile  network of roads designated as important to the U.S. military.
Currently, both the federal government and states fund the construction  and maintenance activities on the Interstate Highway System. Each year,  billions of dollars are provided to the states for the construction and repair  of highways through various highway programs. Under one such  program—the Interstate Maintenance Program (IM)—federal funds  support projects for resurfacing, restoring, rehabilitating, or reconstructing  portions of the Interstate System. Those projects generally require a 10  percent state match, while projects on other classes of roads generally  require a 20 percent match. Under certain circumstances, states may  transfer funds among various highway programs. For example, subject to  certain limitations, states may transfer IM funds to other programs and use  them on other classes of roads (with a 20 percent match). Similarly, states  may also transfer funds from other funding categories to their IM program  and use them for qualifying projects on Interstate highways. The Interstate  Maintenance Discretionary Program provides funding for the kinds of  projects funded under the IM program. In addition, Bridge Discretionary  Program funds can be used on Interstate bridges. FHWA solicits candidates  for the discretionary programs and selects projects for funding from  applications. Finally, the Highway Bridge Replacement and Rehabilitation  Program provides funds for states to replace or rehabilitate deficient  highway bridges located on any public road, including the Interstate  System.
In 1991, we reported on Interstate conditions. In that report, we raised  concerns about the poor condition of Interstate highways and about  FHWA’s oversight of them. Among other things, we suggested that the DOT  report to Congress on the levels of investment required for Interstate  maintenance and on the progress being made to achieve adequate  maintenance.   DOT included information in Appendix A of the 1999  Conditions and Performance Report that was partially responsive to this  recommendation.
section_title: The Role of the Interstate Highway System Has Expanded Over Time
paragraphs: According to state officials, the Interstate Highway System plays an  important and expanding role in the country’s transportation system. The  original purposes of the system were to provide for efficient long-distance  travel, support defense requirements, and connect metropolitan and  industrial areas. Most states agree that these roles continue to be important  but emphasized that several additional important roles have emerged in  recent years. For example, most state officials see the Interstates as  increasingly supporting economic growth and moving freight, as well as  getting passengers to airports and supporting urban travel.
subsections: section_title: Interstates Were Developed to Support Long-Distance Travel and National Defense and Connect Metropolitan Areas
paragraphs: The Interstate Highway System was primarily developed to address (1) the  public’s demand for efficient long-distance travel, (2) the needs of the  military, and (3) the nation’s economic development through the  connection of metropolitan and industrial areas. The expectations for the  Interstate Highway System are described in the following sections.
The public’s desire for easy long-distance travel manifested itself in the  early 1900s through an increase in car ownership and a growing interest  in cross-country travel. Along with this increase in vehicle ownership  came a significant increase in travel and tourism, quickly making cross- country travel a major recreational activity for millions of Americans.
The system allows the nation’s military a means to expeditiously reach  military cross-country installations and ports for deployment. In 1922,  the United States Army developed the “Pershing Map,” which illustrated  for the first time the major roads of prime importance during times of  war. Each of the routes that the Army identified in the map was included  with those roads eligible for federal aid. The military importance of the  Interstate System was emphasized in 1956 when legislation named the  Interstate Highway System the National System of Interstate and  Defense Highways.
By connecting metropolitan and industrial areas, the Interstate System  was also meant to promote the nation’s economic growth and  development. Without an efficient, far reaching national highway  system, merchants found it difficult to move their goods to market in a  timely manner. The 1944 Interregional Highways report explained  that the Interstate System was also intended to serve the nation’s  economic needs in agricultural production, mineral production, forestry,  and manufacturing centers.
section_title: Interstates’ Role in Moving Freight and Supporting Economic Development Have Increased in Importance
paragraphs: According to state officials, the previously mentioned roles continue to be  important, but the role of the Interstate System in freight movement has  increased significantly. State officials we spoke with said that the Interstate  System plays a significant role in their economy by facilitating the  movement of goods by truck. State officials are concerned about economic  development in their states and see the Interstates, especially in terms of  freight movement, as playing a significant role in economic development.  In responding to our survey, officials reported that today, after affording  safe transportation, the most important roles of the Interstates include  moving freight and supporting economic development. (See fig. 4 for the  number of states classifying the importance of different Interstate  functions.) Officials from 33 states indicated that supporting their state’s  general economic development is a very great role for the Interstate  System. Officials from 35 states responded that moving freight through  their state is a very great role for their Interstates, and 30 states believed  that moving freight within their state is a very great role.
According to state officials, moving freight on their Interstate System is an  important focus of their transportation programs. For example, state of  Florida transportation officials told us that although reducing congestion  for cars is important, maintaining mobility for freight traffic on their  Interstate System is very important for industries in their state. For  example, three Interstate routes connect the state’s dairy industry with  other areas of Florida, which consume 85 percent of the milk produced in  the state. In addition, Ohio’s survey response indicated that the Interstate  System was very important for moving freight. The state estimates that its  Interstate and multilane freeway system currently carry about 85 percent of  all the state’s freight and “Keeping the state’s Interstate ystem moving  smoothly and freely is not only important to the economy of the state, but  also to the nation’s economy.”
The role of the Interstate System in carrying freight has increased  significantly over the past 20 years. According to our survey results, 45 of  the state departments of transportation reported that the role of the  Interstate System in moving freight through their state had increased;  officials from 43 states responded that the Interstates had a greater role  moving freight within the state.
Our nation’s freight is currently moving extensively by truck on the  Interstate System, and this movement is important to economic  development. The most recent U.S. Commodity Flow Survey (1997)  reported that trucks carry over 69 percent of the tons shipped in the United  States and 72 percent of the value of goods shipped in the country. In  addition, truck traffic on the Interstates made up over 41 percent of total  truck miles traveled in 2000. An FHWA report and a consultant’s report  explain that freight movement has significantly contributed to improving  the country’s economic efficiency and productivity by, among other things,  making “just-in-time” delivery more feasible, thereby reducing warehouse  and manufacturing costs.
section_title: Roles Supporting Urban Mobility Are Becoming More Important for Interstates
paragraphs: Officials from 39 states identified the Interstate System’s support of travel  within metropolitan areas as a great or very great role. Officials from 33 of  the states said that this role has become greater in the past 20 years. When  the Interstate System was planned, it was expected to provide efficient  travel through the country and to connect major metropolitan areas where  feasible. However, according to FHWA, Congress never expected the  Interstate System to accommodate local traffic. Now a number of trips on  urban Interstates, such as commuting trips, are completed within an urban  area, rather than going through or beyond the urban area. For example,  while urban Interstates make up about 4 percent of all urban lane miles,  they carry about 24 percent of all urban traffic. According to states, the  Interstate System provides efficient urban travel, and as such, urban users  want easy access to it. In addition, according to North Dakota officials, the  urban area of Fargo, North Dakota has encompassed Interstate 29 and the  Interstate is now sometimes used as a local street.
Finally, some of the states that we surveyed said that Interstate highways  are increasingly important for moving people to specific locations that may  not have been seen as important when the Interstate was designed. For  example, 30 states reported that moving people to airports is a greater or  much greater role now than previously. Airport enplanements have grown  rather steadily over the past 20 years—increasing by almost 129 percent  from 1980 through 2000.
section_title: Both the Federal and State Governments Have a Role in Managing and Funding the Interstate System
paragraphs: Since establishing the Interstate Highway System, the federal government  has provided both funding for and oversight of the system. While still  providing funding for the system, the federal government’s oversight focus  is currently on ensuring that states have the procedures in place to manage  the Interstates, as well as providing some project-level oversight. State  departments of transportation manage most of the “hands-on” work of  constructing, maintaining, and planning for the future of the Interstate  System. States also fund a portion of Interstate projects, though to a much  smaller extent than the federal government.
subsections: section_title: The Federal Government Funds the Interstate Highway System and Oversees States’ Management of the System
paragraphs: Congress, FHWA, and the Department of Defense (DOD) play important  roles with respect to the Interstate Highway System, including funding and  overseeing state planning activities, and financing the majority of  construction and maintenance of the system.
subsections: section_title: Congress Establishes and Funds Highway Programs
paragraphs: By passing authorization and appropriations legislation, Congress plays a  significant role with respect to federal highway programs, including  Interstate-related programs.   Authorization legislation, such as the  Intermodal Surface Transportation Efficiency Act of 1991(ISTEA) and the  Transportation Equity Act for the 21st Century (TEA-21), enacted in 1998,  provide funding for various highway programs and related activities,  establish mechanisms for the distribution of those funds, and set forth  eligibility requirements for the highway programs, including the Interstate  programs, limiting how the funds made available may be used. Among  other things, annual appropriation acts make amounts from the Highway  Trust Fund available for payment of obligations incurred for various  highway programs.
Funding for the Interstate System has been a major part of total federal  highway funding, since 1954, when federal funding for Interstate  construction began. However, the proportion of apportionments to states,  specifically for the Interstate activities, has decreased over time as  compared with overall highway program apportionments.
In 1960, the annual Interstate apportionment was $12.2 billion (in 2001  dollars), or 72.8 percent of that year’s federal highway apportionments  to states.
From 1954 through 1991, total apportionments for Interstate  construction and preservation reached $331.2 billion, or 56.8 percent of  federal highway funding apportioned to states for the period.
From 1992 through 2001, Interstate highway apportionments were $39.1  billion, or 17.5 percent of funding apportioned to states. With ISTEA,  Congress scaled back funding apportioned to states specifically for  Interstate highways to $23.9 billion or 20.3 percent of federal highway  apportionments from 1992 through 1997. In addition, Interstate  apportionments were $15.2 billion, or 14.3 percent, of federal highway  apportionments for the next 4 years under TEA-21. (See fig. 5.) ISTEA  also created the NHS and the Surface Transportation Program. Those  programs accounted for 18.0 percent and 21.8 percent, respectively, of  the $223.8 billion in federal highway apportionments made to the states  from 1992 through 2001.
As Congress considers reauthorization of the surface transportation  programs in 2003, it will face decisions about the continued level of federal  involvement in managing and financing the Interstate System.
Even after providing final funding for Interstate completion in 1991,  Congress has continued to designate new Interstate routes. In 1991,  Congress also found that the Interstate System, or comparable highways,  did not adequately serve many of the nation’s regions and identified high- priority corridors for development on the NHS to help meet the demands  for increased capacity. Since 1991, 43 of these high-priority corridors have  been designated, 10 of which were designated to become part of the  Interstate System. In addition, authorization and appropriations acts have  designated funding specifically for certain identified high-priority projects,  which may include improving access to Interstate highways, reconstructing  Interstate interchanges, extending Interstate highways, or performing work  on roads other than Interstates.
section_title: FHWA Oversees State Activities
paragraphs: FHWA’s role in managing the Interstate System has changed from project- specific oversight to primarily overseeing state processes and procedures  and specific projects. While FHWA was heavily involved in selecting routes  for the Interstate System, for overseeing their construction, and ensuring  that the system was adequately maintained, much of the responsibility for  managing them now falls to the states. FHWA is also responsible for  overseeing certain high-cost projects on the Interstate System. FHWA  reviews and approves project designs; approves plans, specifications, and  estimates; concurs in contract awards; and inspects projects.
Today, FHWA does not have significant responsibilities for Interstate  maintenance. For about two decades—until 1998—each state was  required by statute to annually certify that the Interstate highways in their  state were being maintained in accordance with federal requirements. The  law authorized sanctions against states that did not adequately maintain  their Interstate highways; but, they were rarely applied. TEA-21 repealed  the statutory provisions regarding maintenance certification in 1998.  However, if FHWA finds that highways constructed with federal funds are  not being properly maintained, it is required to inform the state and  withhold federal approval of future state-highway projects in all or part of  the state if the condition is not corrected within 90 days.
Although construction of the Interstate System is essentially complete, the  agency may approve additions to the existing Interstate Highway System  when states request such an addition. When FHWA receives requests for  additions to the existing system from states, it considers, among other  things, whether the proposed new segment is a logical addition or  connection to the Interstate System and whether it meets Interstate  geometric and safety standards. Although both Congress and FHWA  designate specific additions to the Interstates, the nation does not currently  have a centralized system for determining whether new routes are needed  and building them. Similarly, the agency approves adding access points  (interchanges and ramps) to the existing system and system design  exceptions.
FHWA is also responsible for overseeing states’ planning processes by  reviewing and approving statewide transportation improvement programs  (STIPs). These federally required plans cover at least 3 years and describe  the state’s planned construction, maintenance, and other highway projects,  including Interstate projects. FHWA’s review of the STIP primarily focuses  on whether the required processes were followed rather than on the  content of the plan. (See app. III for more details about the planning  process.)
FHWA also has other responsibilities related to the Interstate System. For  example, the agency sets performance goals, as required by the  Government Performance and Results Act of 1993 (Results Act), for  pavement quality, bridge condition, highway congestion, and safety.  Although FHWA does not have Interstate-specific performance goals, its  performance goals do include Interstate highways. For example, FHWA’s  safety goal is to reduce highway fatalities and injuries by 20 percent by  2008. FHWA’s performance goal for pavement quality applies to the NHS,  which includes the entire Interstate System. These are FHWA’s goals, and  states are not required to meet them for their Interstates or other roads.  Finally, other FHWA responsibilities include providing technical assistance  and management tools, such as investment-analysis models, to aid in the  planning process at state transportation agencies; conducting  transportation-related research; and disseminating the results throughout  the country.
section_title: DOD Works with FHWA and States to Meet Defense Requirements
paragraphs: DOD played an important role in establishing the Interstate Highway  System. However, state officials reported that this role has not increased  significantly in the past 20 years. DOD participated in selecting the  Interstate highway routes, and according to DOD and FHWA officials, DOD  works with federal and state transportation officials to ensure that the  Interstate System meets its national defense requirements. In 1981, DOD, in  partnership with FHWA, identified public highways to make up the  STRAHNET. This network of highways gives the military the ability to  move equipment and personnel expeditiously over the highway system  from military installations to ports for deployment. The STRAHNET  consists of 61,044 miles plus 1,700 miles of connectors that link over 200  important military installations and ports to the network. All of the nation’s  Interstate highways are included in the STRAHNET. STRAHNET and its  major connectors were incorporated into the NHS in 1995. This continues  to emphasize the military importance of these highways. According to DOD  officials, the working relationship between DOD and FHWA, and the  conditions on the Interstate System, are adequate.
section_title: States Plan, Construct, Maintain, and Help Fund the Interstate System
paragraphs: States handle many of the responsibilities for managing the Interstates as  well as providing some funding. State responsibilities include developing  plans for maintaining the physical and operational conditions and the  safety of Interstate highways. States are required to develop at least two  planning documents—a 20-year Statewide Transportation Plan and a short- term Statewide Transportation Improvement Program (STIP) that covers at  least 3 years. The plans outline how the states will use available funds to  maintain the physical and operational conditions and the safety of their  Interstates. To develop these planning documents and maintain their  Interstates, states use a variety of approaches. See appendix III for a  description of states’ planning processes. In addition, state departments of  transportation are responsible for the day-to-day operations of  constructing and maintaining the Interstates. Finally, state governments  provide some funding for the Interstate Highway System; however, they  spend less on the Interstates than does the federal government.   States  raise highway funds to match federal funds and to pay for other state  highway projects and programs.
section_title: Since 1992, Most Interstate Highway Investments Have Been for Preservation or Capacity Additions
paragraphs: The federal and state governments have invested heavily in Interstate  highways. Because 97.4 percent of the system’s length in 2000 was  complete before 1992, much of the subsequent investment was to preserve  and maintain the existing system. When states added to the system’s size,  they did so mainly in urban areas. From 1992 through 2000, the type of  Interstate pavement and bridge construction projects also shifted from new  construction to primarily maintenance.
subsections: section_title: Overall Spending on Interstates Has Grown
paragraphs: Outlays, that is, expenditures of federal, state, and other funds for projects  on Interstate highways have generally increased since 1992. State spending  of federal, state, and local funds for Interstates grew from $13.0 billion in  1992 to $16.2 billion in 2000. States reported total capital outlays for  Interstates of $105 billion, or an average of $11.7 billion per year in 2001  dollars from 1992 through 2000. (See fig. 6.) Besides capital outlays, states  also had routine Interstate maintenance outlays that averaged $1.6 billion  per year. These outlays, which generally consist of nonfederal funds, were  for routine tasks like sealing cracks and patching potholes, which help  keep the pavement in good condition, but did not cover capital  improvements like resurfacing, rehabilitation, or reconstruction.
section_title: States Have Spent More on Urban Interstates
paragraphs: From 1992 through 2000, states allocated more of their Interstate  investments of federal, state, and other funds to urban highways (68.4  percent of outlays) than to rural highways (31.6 percent of outlays).  Furthermore, states have invested higher levels of state or local funds in  urban projects than in rural projects. Specifically, federal Interstate  obligation data for projects show that, from 1992 through 2000, rural  Interstate projects averaged 11.2 percent in state or local funding, while  urban projects averaged 15.1 percent in state or local funding. (See fig. 7.)
section_title: States Are Spending More for Preservation of Pavement and Bridges
paragraphs: States spent available funds for different types of projects on their  Interstate Systems, including pavement, bridge, and other related items  (including safety, traffic operations, and environmentally related projects).  FHWA reported obligations of $48.5 billion for Interstate highway projects  from 1992 through 2000. Of this amount, 66.2 percent, or $32.1 billion, was  for pavement projects, 19.7 percent, or $9.6 billion, was for bridge projects,  and the rest, $6.8 billion, was for other related items. (See fig. 8.)
Accounting for the largest area of expenditures, Interstate pavement  projects since 1992 were clearly focused on existing roadways. Among  pavement project miles, 98.6 percent were to improve existing highways;  only 1.4 percent for new construction. (See fig. 9.) Costs for improving  existing highways were $29.0 billion, or 90.2 percent of total pavement  costs. Only 424 miles, or 1.4 percent of Interstate projects’ length, were for  new construction. (See fig. 10.) Costs for new construction were $3.1  billion, or 9.8 percent of total pavement costs.
Interstate pavement construction projects from 1990 through 2000 shifted  toward maintaining the existing system. Based on FHWA obligation data,  new pavement construction project miles declined during the period, while  reconstruction project miles tended to decline during the period and  pavement maintenance project miles—restoration and rehabilitation, and  resurfacing—increased.
In addition, Interstate bridge projects were more likely for preservation or  replacement than for new construction. Among the 11,530 bridge projects  reported, 10,363, or 89.9 percent, were replacement or rehabilitation  projects.
section_title: Most Interstate Conditions Have Improved, but Congestion Has Grown
paragraphs: The Interstate’s physical conditions (pavement and bridge) and safety are  in good overall shape; however, congestion has grown. Pavement  conditions improved from 1992 to 2000, and officials from 39 states now  regard their pavement as good or excellent. Officials from a majority of  state highway departments predict pavement will still be in good condition  10 years from now. However, officials from 23 states predict that, in 10  years, they will be falling behind in dealing with the condition of their  Interstate pavement. Bridge conditions parallel pavement conditions: since  1992, bridge conditions have generally improved, and officials from a  majority of states report bridge conditions are currently good or excellent,  but officials from 19 states predict the condition of their bridges will  worsen 10 years from now. Safety on the Interstate System has remained  relatively stable. Interstate fatality rates declined from 1990 to 1992 and  remained fairly stable after 1992. A majority of state officials rated the  safety of travel on their Interstates as good or excellent today, and 41  predicted it will remain so 10 years from now. Moreover, DOT data showed  that pavement, bridge, and safety conditions are better on Interstates than  on other roads. But unlike pavement, bridge, and safety factors, Interstate  congestion has gotten worse. One measure showed that rush hour travel  time on urban Interstates increased 12 percent from 1990 through 2000.  State officials in nearly half of the states reported that urban congestion is  already high, and officials from 41 states predicted it will be high 10 years  from now. State officials reported high rural congestion in only 1 state now,  but expected it in 18 states within 10 years.
subsections: section_title: Pavement Conditions Have Improved
paragraphs: Generally, Interstate pavement conditions have improved since 1990.  According to FHWA data, 8.6 percent of Interstate pavement, or 3,897  miles, was in poor condition in 1990. By 2000, the share of poor Interstate  miles had dropped to 3.4 percent, or 1,560 miles. In addition, pavement  data for 1990 through 2000 show that urban Interstates have a higher  percentage of poor mileage than rural Interstates, but both have improved  since 1990 (see fig. 11). The improvement pattern was not continuous  partly because FHWA asked the states to adopt a new condition measure.  States had historically reported pavement condition using a subjective  rating scale. By 1992, states were also reporting pavement data with a more  objective statistic called the International Roughness Index. In 1993, FHWA  adopted the roughness index as a required statistic for reporting pavement  conditions on Interstates. States needed new measuring devices to adopt  the International Roughness Index. When these devices were later  upgraded, some states such as North Dakota, noticed an improvement in  their pavement condition statistics.
Two factors may have contributed to the long-term improvement in  Interstate pavement. First, the federal government has increased its  commitment to pavement quality, along with highway funding in general.  FHWA has supported quality pavement management by promoting better  planning and techniques for building smoother, longer-lasting roads. In  addition, state highway programs have received increased federal funding  since TEA-21 “guaranteed” certain overall funding levels based on Highway  Trust Fund revenue. (See fig. 6 for increases in Interstate capital outlays  during this period.) Second, state transportation departments have  increased their commitment to Interstate pavement quality. This  commitment may be ongoing, as in Florida, which adopted a statutory  requirement in 1984 requiring goals for the quality of the pavement on its  state highways. Or the commitment may come in response to customer  feedback, as when Pennsylvania initiated a pavement upgrade program in  response to truckers’ surveys criticizing conditions on the state’s roads.
subsections: section_title: Interstate Pavement Is in Good Overall Condition, but Some Sections Are in Poor Condition
paragraphs: Of 51 respondents, 39 states reported that their Interstate pavement is  currently in good or excellent condition; 9 said that their pavement is in fair  condition; 3 reported poor Interstate pavement conditions; and none  reported very poor conditions. (See fig. 12.) In addition, state pavement  data submitted to FHWA for 2000 showed that for the nation as a whole,  63.5 percent of pavement was in good or very good condition, 18.2  percent was in fair condition, and 18.3 percent was in mediocre or poor  condition. Half of the states reported that less than 2.0 percent of their  pavement was in poor condition. FHWA’s pavement categories describe a  pavement’s need for upcoming improvement as interpreted from a  roughness index.
Rural Interstate pavement, which gets less heavy traffic, is in better  condition than urban Interstate pavement, according to data that the states  supply to FHWA. According to an FHWA report on pavement conditions in  2000, only 14.4 percent of rural mileage is in poor or mediocre condition,  compared with 28.2 percent of urban mileage.
While the overall condition of Interstate pavement is generally good, it is  much worse in certain states than our aggregate survey responses or  nationwide pavement condition statistics suggest. For example, according  to FHWA data, while 18.3 percent of the nation’s Interstate pavement is in  mediocre or poor condition, 10 states have at least one-third of their  pavement in mediocre or poor condition. Four of these states have more  than 12.0 percent of their pavement in poor condition, compared with a  nationwide rate of 3.4 percent for pavement in the poor condition category.  Missouri, one of our case study states, has 4.1 percent of its Interstate  pavement in the poor category, fairly close to the nationwide level.
However, 40.1 percent of its Interstate pavement is in mediocre condition.  According to a draft long-range transportation plan, many of Missouri’s  Interstates need total reconstruction. State officials said that they plan to  focus on I-70 between St. Louis and Kansas City, one of the oldest segments  on the Interstate System, where, by state criteria, one-third to one-half of  the pavement is poor or very poor.
Compared with “other major arterials,” Interstates are in better condition  in both rural and urban areas. According to Interstate standards, in urban  areas, 6.5 percent of Interstates are in poor condition, compared with 27.0  percent of other “urban major arterials.” In rural areas, 2.1 percent of  Interstates are in poor condition, compared with 4.0 percent of “other  major arterials.” (See fig. 13.)
FHWA has no requirements or standards for states to keep their Interstate  highways in a particular condition. However, FHWA’s Fiscal Year 2002  Performance Plan included a pavement condition goal for the NHS, which  includes the Interstate Highway System. FHWA originally determined that,  by 2008, 93 percent of NHS pavement should have acceptable ride quality— meaning an International Roughness Index of 170 inches per mile or less.  As a whole, the NHS had met this goal as of 2000, and the Interstate portion  of the NHS met this goal by 1996. Since the 2008 goal had already been met,  FHWA revised its performance goal. The current goal emphasizes that  highly traveled roads should be in good condition and requires that, in 2002,  92 percent of vehicle miles on the NHS will be traveled on pavement that  meets the acceptable ride standard.
section_title: Expectations of Future Interstate Pavement Conditions Vary
paragraphs: We did not find agreement on whether Interstate pavement conditions will  be as good in a decade as they are now. A majority of state officials  responding to our survey predict that Interstate pavement will still be in  excellent or good condition 10 years from now. However, 21 respondents  predict that their pavement will be in fair or worse condition. Compared  with their assessments of current conditions, our respondents’  assessments of future conditions predict less pavement in good or  excellent condition and more pavement in fair, poor, or very poor  condition. Officials from 23 states predict that, in 10 years, they will be  falling behind in dealing with the condition of their Interstate pavement. In  addition, officials from 44 states predict that the portion of their  transportation spending devoted to improving Interstate pavement  conditions will increase (27 states) or stay the same (17 states). (See fig.  14.)
DOT recently predicted that, given expected future investment levels,  states could improve Interstate pavement conditions over a 10-year  planning period. However, DOT’s primary funding projection could be  higher than states assumed in responding to our survey. DOT projected that  states would increase their Interstate funding levels from 2.8 to 3.0 percent  annually in constant dollar terms from 2003 to 2007, consistent with  historic trends. State officials might not assume such funding increases,  according to a FHWA official. Thus, the funding level in DOT’s analysis  might be higher than state officials expect, which could account for DOT’s  prediction of better future pavement conditions.
section_title: Interstate Bridge Conditions Have Generally Improved
paragraphs: The number of deficient Interstate bridges has declined over the last 8  years. Specifically, the number of structurally deficient bridges declined by  over 22 percent from 1992 through 2000. In addition, FHWA information  also shows that the bridge deck area associated with structurally deficient  Interstate bridges decreased by over 27 percent during the same period.  Structurally deficient bridges can have restrictions on the weight of  vehicles using them or may need to be closed and repaired before they can  be used again. In addition, the number of functionally obsolete bridges  declined by more than 10 percent over the same period. However, the deck  area associated with functionally obsolete bridges increased 9 percent over  this period. Functionally obsolete bridges are not up to design standards  and generally face less serious problems than structurally deficient  bridges—for example, shoulders that are not as wide as the roadway  leading to the bridge. Figure 15 shows the decreasing trend in number of  deficient bridges.
Overall, state officials responding to our survey reported that their bridges  are currently in good condition. Of the states responding to our survey, 31  said that the overall condition of their Interstate bridges is good or  excellent; another 19 said it is fair. As of April 2001, 5 percent of the nation’s  Interstate bridges were structurally deficient. In addition, another 16  percent were functionally obsolete.
Interstate bridges are generally in better condition than those on other  classes of roads. According to 1998 FHWA data, about 27 percent of urban  Interstate bridges were deficient, compared with a range from over 27  percent for “urban other freeways and expressways” to over 38 percent for  both “urban minor arterials” and “urban collectors.” In addition, 16 percent  of rural Interstate bridges were deficient, compared with a range from 17  percent for “rural other principal arterials” to over 36 percent for “rural  local roads.”
subsections: section_title: Expectations of Future Interstate Bridge Conditions Vary
paragraphs: Some state officials said that they are optimistic about future bridge  conditions—24 expect conditions 10 years from now to be good or  excellent. However, others are aware of problems bridges could face in the  future. Nineteen state respondents believed that their state would fall  behind in maintaining the condition of their bridges over the next 10 years,  given the expected level of funding. However, they were not as concerned  about falling behind on their Interstate bridges, as they were about the  problems they would face with congestion and pavement condition. (See  fig. 21.) In addition, officials from 32 states expect to increase the portion  of their budget spent on Interstate bridges.
section_title: Interstate Safety Has Been Mainly Stable
paragraphs: The fatality rate on the Interstate System has been relatively steady, after  falling early in the 1990s. The number of fatalities on Interstate highways  has increased over the past decade, but so has the level of traffic, as  indicated by the number of vehicle miles traveled (VMT). (See fig. 16.)
Relatively speaking, Interstate highways are the safest of all highway  classifications. We recently reported that among urban road types, “other  principal arterial” roads had the highest 1999 fatality rate at 1.27— compared with 0.61, the lowest fatality rate, on urban Interstate roads.  Similarly, we reported that among the rural road types, “rural local roads”  had the highest 1999 fatality rate at 3.79—compared with 1.24, the lowest  fatality rate, on rural Interstate roads. In addition, 45 states we surveyed  said that the current level of safety on their Interstates was good or  excellent.
Several factors, including unique design characteristics, may contribute to  the Interstate System’s higher level of safety. According to a 1999 FHWA  report, most of the Interstate mileage in the country met geometric design  criteria that support safe transportation in 1997. These criteria refer to the  physical layout or alignment of a roadway. FHWA and states recognize  guidelines established by the American Association of State Highway and  Transportation Officials (AASHTO) as the appropriate design standards  for many of their roads.   The Interstate System meets these guidelines to a  great extent—over 99 percent of urban Interstate mileage and about 97  percent of rural Interstate mileage. Almost all of the rural Interstate  mileage not meeting the guidelines is in rural Alaska; about 50 percent of  the urban Interstate mileage not meeting the guidelines is in Puerto Rico.  Other design characteristics are also important to safety:  According to FHWA, the vast majority of Interstate mileage has full  access control—which FHWA policy classifies as critical to  maintaining Interstate safety and mobility. Research shows that  highways without access control have higher crash rates than those  with access control.
According to FHWA, the vast majority of Interstate mileage also consists  of divided highways with at least four lanes. AASHTO’s guidance reports  that a study on the effect of the Interstate Highway System on crashes  found a lower crash rate on divided highways than on undivided  highways.
The uniformity of Interstate highway design plays a part in safety by  reducing the number of decisions drivers make and thus minimizing the  number of crashes related to driver error.
FHWA also believes that other factors, including increased seat belt use  and reduced alcohol-impaired driving, have contributed to lowering the  fatality rate and the number of fatalities on the nation’s highways— including Interstate highways.
subsections: section_title: Interstates Are Expected to Remain Safe
paragraphs: State officials responding to our survey expect the safety of Interstate  travel in their states to remain relatively safe. Among 51 responses, 41 said  the safety of Interstate travel in 10 years will be good or excellent, 9 said  travel safety would be fair, and 1 said safety would be poor. A majority of  officials—29—said the portion of state transportation spending for  improving safety in their states would stay about the same over the next 10  years, though 19 predicted some increase or a moderate increase.
section_title: Interstate Highways Have Become More Congested
paragraphs: As congestion on the country’s roadways has increased, so has congestion  on the Interstate System. Whether measured in terms of traffic density or  travel time, congestion has increased over the past decade. Furthermore,  Interstate highways are generally more congested than other freeways and  other principal arterials.
While there is no single indicator for congestion, we looked at FHWA’s  “daily vehicle miles traveled per lane mile” to measure traffic density. As  figures 17 and 18 show, the overall density of traffic on all major U.S. roads  has been increasing over the past decade and traffic density is higher on  urban highways than on rural ones. In addition, the traffic density on  urban Interstate highways is higher than on other classes of urban road.  (See fig. 17.)
Although the density of traffic on urban Interstate highways is higher than  on rural Interstates, traffic on rural Interstate highways is increasing at a  faster rate than on any other classes of road. From 1990 through 2000, the  daily vehicle lane miles traveled on rural Interstates increased at an  average annual rate of 3.3 percent. By comparison, the daily vehicle lane  miles traveled on rural principal arterials increased at an annual rate of 1.9  percent. (See fig. 18.) In addition, daily vehicle miles traveled on urban  Interstates increased at an annual average rate of 1.7 percent, and the rate  increased by 1.3 percent on other urban freeways and expressways.
While daily vehicle lane miles traveled measures traffic density, it does not  indicate the effect of congestion on drivers, especially the amount of time it  takes them to reach their destinations. The Texas Transportation Institute  has developed measures that address a central concern of urban drivers— how travel time is affected by congestion. One measure—the travel time  index—indicates how much more time it takes to travel during a peak  period than at other times of day. The travel time index indicates that urban  Interstate congestion has increased from 1990 through 2000, and  congestion levels are higher on the urban Interstate System than on any  other class of roads, including urban freeways and expressways and urban  principal arterials. (See fig. 19.)
During the past decade, the travel time index increased by about 12  percent. This statistic provides information about drivers’ experiences as  well as the level of congestion on the road because it accounts for delays  due both to the traffic demand on the road and to roadway incidents, like  accidents. For example, a travel time index of 1.63 means that a trip that  takes 30 minutes in an off-peak (noncongested) period would, on average,  take 63 percent longer, or almost 19 extra minutes in the peak period—in  other words, the trip would take an average of about 49 minutes rather than  30 minutes when the road is congested. In addition, the Texas  Transportation Institute data show that delay from incidents is greater than  recurring delay from traffic. Specifically, their Mobility Report 2001 states  that delay from incidents accounts for 54 percent of total delay.
Many factors can contribute to congestion. As figure 20 shows, increases in  overall population and the number of licensed drivers are factors that could  each cause more cars to be on the road during peak hours. The Census  Bureau reports that, from 1990 to 2000, the population increased by about  13 percent nationwide. In addition, according to FHWA, the number of  licensed drivers increased by 14 percent during the past decade. These,  along with other factors, resulted in a 39 percent increase in the number of  miles traveled in the United States in the past decade. Freight movement by  truck also increased by 40 percent over the first 8 years of the decade.  However, Interstate capacity in terms of lane miles increased by only 6  percent over the past decade. Finally, expansion of metropolitan areas and  the choices people make about where they live and work also contribute to  congestion.
Officials from 24 states rated the present level of congestion on their urban  Interstates as “high” or “very high,” and officials from 21 states rated their  urban Interstate congestion as “average.” By contrast, no officials rated  rural congestion as “very high,” and just one official rated the level of  congestion on rural Interstates as “high”; officials from 27 states rated  congestion on their rural Interstates as “average.”
In response to our survey, nearly all states expressed concern about future  congestion on their urban Interstates. For example,   42 states predicted that, 10 years from now, they would be falling behind  in terms of alleviating urban congestion and   41 states expected to rate urban congestion in the next 10 years as high  or very high. (See app. II.)
State respondents generally do not expect that their efforts to alleviate  congestion will be entirely successful. Although 34 states indicated that  they expect to spend a greater portion of their budget on urban congestion  over the next 10 years, 42 states believe they will be falling behind in  dealing with urban congestion. In addition, in its 1999 Condition and  Performance report, FHWA predicted that congestion would worsen—that  is, average travel time costs would continue rising—if investment and  allocations stay at the current expected levels. In its reauthorization of  surface transportation programs, Congress could decide to select methods  for investing federal resources in the Interstates and other highway  programs to help address local congestion problems in urban areas. To  assist in making these decisions, we asked states about policies and tools  that can be used in alleviating congestion. (See app. IV for the states’  responses.)
Although states are particularly concerned about urban congestion levels,  they also think that rural congestion will increase, especially on specific  routes. Officials from 18 states expect to rate rural congestion as “high” or  “very high” in the next 10 years.   For example, rural congestion is  increasing on the I-70 corridor—a 140-mile-long stretch through the Rocky  Mountains of Colorado. This section serves in moving skiers and truckers  through the mountains. However, traffic congestion has become an  increasing problem along this corridor, in part due to population growth in  the surrounding areas—and will continue to worsen over the years.
section_title: Increases in Traffic, the Age of the Interstates, and Funding Constraints May Negatively Affect Interstate Conditions; However, the Costs to Address These Factors Are Uncertain
paragraphs: States expect certain factors, especially the levels of truck and car traffic,  the age of the Interstates’ pavement and bridges, and funding constraints to  negatively affect the conditions of their Interstates over the next 10 years.  FHWA data also indicate that traffic, especially the volume of truck traffic,  will increase. In addition, many states believe they will be “falling behind”  in satisfying the users of their systems, especially in terms of congestion.  (See fig. 21.) Transportation officials have also indicated that large-dollar  projects may negatively affect states’ financial ability to maintain their  systems. States responding to our survey indicated that they plan to spend  larger portions of their budgets addressing these Interstate pressures.  However, identifying the states’ cost to maintain and improve their systems  is difficult. States’ STIPs, required to include only projects that can be built  with estimated revenues, show how states plan to use the funding they  estimate will be available, rather than the funding they estimate will be  needed for their Interstates. Some states have developed plans that provide  some insight into what it will cost to maintain conditions or reach specific  goals. These estimates indicate that states perceive Interstate needs as  larger than estimated funding.
subsections: section_title: Increasing Truck Traffic to Have Greatest Negative Effect on Interstate Conditions
paragraphs: According to our survey, states expect truck traffic to have a negative effect  on the most elements of Interstate conditions including physical conditions  (pavement and bridges), safety, and rural congestion. (See table 1.) For  example, all 52 states expect truck traffic to increase over the next 10  years, and 49 states said that they expect this to negatively affect the  condition of their pavement. Current estimates used by FHWA also show  freight movement by truck increasing by 28 percent from the end of 2001  through the end of 2010. Finally, an alliance of primarily southern and  southeastern states released a 2001 study that estimates an annual 6.9  percent increase in Latin American truck traffic in the United States  (resulting in almost a doubling in 10 years). Ninety-six percent of this truck  traffic will be on Interstates.
State officials’ concerns about increases in truck traffic may reflect, in part,  the estimated highway costs of damage to the pavement or bridge of each  additional truck-mile driven compared with the cost of a car. A recent  FHWA study explains that while car drivers pay about the same share of  user taxes as their share of highway costs, heavy truck operators  commonly pay less than their share of highway costs. Specifically, FHWA  estimated that an additional mile of Interstate car travel cost of 0.1 cent in  terms of pavement damage, while an additional mile of Interstate truck  travel had a pavement damage cost as high as 12.7 cents on rural  Interstates and 40.9 cents on urban Interstates. In 1994, we recommended  that FHWA conduct this highway cost-allocation study.
In addition to increases in truck traffic, estimates that FHWA uses show  that passenger traffic will increase by 17 percent from the end of 2001  through the end of 2010—an increase from 2.7 trillion vehicle miles  traveled to 3.1 trillion. States are also concerned about increases in traffic  volume. Of the 52 states we surveyed, 51 predict that overall traffic  volumes will increase over the next 10 years. Fifty-one of the states expect  this increase in traffic volume to negatively affect urban congestion, and 41  of 51 respondents believe that the changes in traffic volume will negatively  affect rural congestion.
Another factor negatively affecting the condition of Interstate pavement  and bridges is the age of the infrastructure. For example, half of the  Interstate bridges are currently over 33 years old. Figure 22 shows when all  Interstate bridges were built. Officials from one state we visited explained  that many of their state’s Interstate bridges were built about 40 years ago  and are reaching the end of their estimated 50-year design life. In addition,  45 states believe age may jeopardize their bridge conditions, while 38 states  expect age to negatively affect their pavement conditions 10 years from  now.
section_title: Cost of Large-Dollar Projects and Other Economic Conditions Could Negatively Affect States’ Highway Programs
paragraphs: Transportation officials are concerned that some states may face an  increasing number of large-dollar projects such as work on bridges or  interchanges that may constrain spending for those states’ other projects  for a number of years. For example, Missouri is looking at reconstructing  the 200-mile I-70 corridor at a cost of $2.5 billion to $3.0 billion. In addition,  the Woodrow Wilson Bridge, which moves north-south traffic on I-95  around Washington, D.C., is expected to cost over $2 billion and is being  funded by two states and FHWA. According to a Maryland official, over the  6-year project, funding for the bridge accounts for 45 percent of  expenditures on major projects in the state’s capital budget.
In addition, 40 states are facing budget shortfalls for 2002. Furthermore, the  amount of funds available for federal highway programs may decrease for  fiscal year 2003, depending on congressional action. These potential  reductions in federal and state funds could reduce the funds available for  maintaining the Interstates and increase states’ estimated funding  shortfalls.
section_title: Costs to Maintain Interstates Are Uncertain
paragraphs: It is difficult to identify state needs on the Interstate System and to  determine what level of funding is needed to meet these needs. When  surveyed, most states indicated that they expect to spend the same or  increasing portions of their transportation budgets to maintain Interstate  conditions. However, when states provided information on their planned  expenditures, the amounts did not show a consistent upward trend, rather  they varied considerably from year to year. (See table 1 in app. III.) State  and FHWA officials explained that one common reason for these increases  and decreases is that work on Interstates is not done in a vacuum; that is,  Interstate projects must be weighed against projects on other classes of  roads, such as expressways or “principal arterials.” For example, North  Dakota officials explained that they are completing projects, which are  focused on improving the condition of their Interstate highways. They  expect to shift their attention and funding toward projects on other classes  of roads.
In addition, states’ federally required plans do not usually provide  information on all needs and related costs. States’ short-term STIPs do not  identify funds needed to maintain Interstate conditions because they  include lists of proposed projects that can be built with estimated  revenues. Therefore, as state and federal officials explain, STIPs reflect  affordability rather than identifying projects that are needed and would be  constructed if additional funding were available. In addition to STIPs,  states are required to develop long-term (20-year) plans. However, these  plans may not contain specific projects and cost estimates, and thus do not  provide information on states’ needs and related costs.
Nevertheless, some states have developed additional transportation plans  that identify long-term funding gaps for various parts of their highway  networks, including the Interstates. For example, North Dakota is  developing a needs estimate for its state roads (excluding urban  Interstates). The state defined its need by using criteria for pavement,  bridge, design, and safety conditions. State officials estimated the funds  needed to bring the roads (except urban Interstates) to the desired physical  condition and level of performance as nearly a billion dollars more than  available. According to state officials, eliminating the backlog will require  either an increase in revenue or a decrease in service. In addition, in 2001,  Florida officials estimated that to meet capacity needs on its Intrastate  System (including Interstates), it would need $20 billion more through  2010 than the $11 billion it expects to have. Missouri’s draft 2000 long-term  plan also indicates that the state’s needs outweigh the available funds.
section_title: Concluding Observations
paragraphs: Interstate highways continue to play a vital role in moving people and  freight in this country. Over the past few decades, however, they have taken  on an important and expanded role in facilitating travel within urban areas.  They have also become central to moving freight and, as a result, to  economic growth. These roles will continue to be important; however, they  have consequences that will challenge the federal government and state  and local governments in assuring that Interstate highways continue to  provide efficient travel and remain in relatively good condition. In  particular, the challenges for Interstate highways include  finding effective methods of easing traffic congestion, particularly in   providing for efficient freight movement given increases in both  passenger and freight traffic; and  responding to the effect of traffic on roads and bridges given the  continued aging of these structures.
section_title: Agency Comments and Our Evaluation
paragraphs: We provided a draft of this report to DOT and DOD for their review and  comment. DOT officials, including the Team Leader for Highway Needs and  Investment Analysis within FHWA, provided oral comments. They  generally agreed with the observations in the report, and they also provided  technical comments, which we incorporated in the report as appropriate.  DOD officials, including the Chief, Office of Special Assistant for  Transportation Engineering, Military Traffic Management Command,  provided technical comments, which we incorporated as appropriate.
We conducted our review from March 2001 through April 2002 in  accordance with generally accepted government auditing standards.
As arranged with your office, unless you publicly announce its contents  earlier, we plan no further distribution of this report until 7 days after the  date of this letter. At that time, we will send copies of this report to  cognizant congressional committees; the Secretary of Transportation; and  the Administrator, Federal Highway Administration.
If you or your staff have any questions about this report, please contact me  at (202) 512-2834. Appendix V lists the key contacts and contributors to this  report.
section_title: Objectives, Scope, and Methodology
paragraphs: With the upcoming reauthorization of the surface transportation programs,  the House Committee on Transportation and Infrastructure asked us to  report on Interstate highways and bridges. Accordingly, this report  examines the condition of the Interstate System, including, (1) how the role  of the Interstate System has changed over time; (2) the roles of the federal  and state governments in managing and funding the Interstate System; (3)  the financial resources that states and the federal government have  devoted to the system; (4) how physical conditions, safety, and congestion  of the Interstate System have changed and how they compare to other  classes of roads; and (5) the factors that could affect future Interstate  conditions and the cost of addressing these factors.
To determine how the role of the Interstate System has changed over time,  we reviewed historical documents. We also conducted a nationwide mail  survey of state transportation agencies in all 50 states, the District of  Columbia, and Puerto Rico. Our survey focused on state officials’ views on  the changing role of Interstate highways in their states’ transportation  systems; the usefulness of various approaches for addressing operations  and maintenance of their Interstate highways and bridges; their views on  the Interstate System in 10 years; and their perceptions of the current  condition of their Interstate System’s infrastructure, safety, and congestion.  We received survey responses from all 52 governments—most states  responded to most of the questions. A summary of responses to the survey  appears in appendix II of this report.
To develop our mail survey, we discussed potential survey topics with state  officials in two states to determine how to design our survey questionnaire.  Then, we conducted pretests of our questionnaire with transportation  officials in four states. We selected states for our survey development  phase to provide perspectives from a variety of geographic areas and from  states with various types of weather, population patterns, and other factors  that affect Interstate planning. Each of the four pretests consisted of a visit  with state officials by our staff to ensure that (1) questions were readable  and clear, (2) terms used were clear, (3) the survey did not place undue  burden on state governments that would result in a lack of cooperation,  and (4) the survey was independent and unbiased in its point of view.  Appropriate changes were incorporated into the final survey based on our  pretesting. In addition to our pretesting, we discussed our questionnaire  with an official at FHWA headquarters and representatives of the AASHTO  in Washington, D.C. We incorporated comments from these discussions, as  appropriate.
To determine which officials should receive our survey, we used AASHTO’s  Reference Book to identify the appropriate state officials. We verified our  selection by contacting FHWA division officials in most of the 52 locations.  During the return period, an unprecedented terrorist incident occurred on  September 11, 2001. Although it is possible that the responses completed  after this date may have differed from those received beforehand, our  analysis of the question of the role of the Interstates in moving military  personnel and equipment shows that answers did not differ for these two  time periods. We received the last survey included in our analysis on  November 21, 2001.
To address our second objective, we reviewed historical Federal-Aid  Highway Program data obtained from FHWA, which discussed why the  Interstate System was developed and the roles Congress, FHWA, DOD, and  states played and how they have evolved into the current roles. We also  interviewed FHWA and DOD staff about their roles and identified current  federal requirements related to the Interstates. Finally, we examined  federal apportionments to the states for Interstates as well as other  activities.
For our third objective, we analyzed FHWA’s obligation of funds for  Interstate-related projects. We also reviewed outlays from all levels of  government for Interstate-related projects, as reported by states on an  annual basis.
For the fourth objective, we used the responses to our survey described  previously. To compare conditions of Interstate highways to other classes  of roads as well as obtain trend information on Interstate highway  conditions, we reviewed DOT’s published data on actual highway  conditions and its forecasts of potential future conditions. To learn how  officials assess Interstate highway conditions in their states, we  interviewed officials in Arizona, Florida, Missouri, North Dakota, and  Pennsylvania. We selected these states to obtain perspectives from a  variety of regions with various types of weather, population differences,  and other factors that affect Interstate planning.
In addition, to determine the current condition of the Interstate System in  terms of congestion, we relied on a number of measures reported by  FHWA. We requested FHWA to obtain Texas Transportation Institute  analysis of congestion levels on Interstate highways in comparison with  other classes of roads. We also reviewed DOT’s Bureau of Transportation  Statistics and U.S. Census Bureau data on factors related to congestion  trends. Furthermore, to assess safety, we reviewed data from the National  Highway Traffic Safety Administration’s Fatality Analysis Reporting  System, and FHWA data on trends in fatality rates and number of fatalities.
To address the last objective, we analyzed state survey responses and  discussed the factors with state and FHWA officials during our site visits,  as necessary. We focused on factors such as demographic changes or  changes in traffic, but we did not focus on the influence of federal funding  through the existing Federal-Aid Highway Program on state’s decisions  about their investment in Interstate roads and bridges. To examine states’  plans for Interstate investment, we asked states to provide information on  their planned costs for their Interstate highways in our survey. We reviewed  states’ written plans for investment in Interstate highways and other roads.  Again, we also visited the five states mentioned earlier to obtain more  detailed information on their planning. Additionally, we interviewed FHWA  division officials to obtain a general overview of FHWA’s approach to  assisting states with their Interstate System plans.
We conducted our review from March 2001 through April 2002 in  accordance with generally accepted government auditing standards.
section_title: Survey of States’ Views on the Future of the Interstate System
section_title: State Planning Processes
paragraphs: States must meet specific planning requirements set forth by federal law. In  addition, state transportation agencies may face state-level requirements.  Within these requirements, states develop plans to allocate available funds  throughout their transportation systems.
Federal law requires each state to develop at least two planning  documents—a 20-year Statewide Transportation Plan and a short-term  Statewide Transportation Improvement Program (STIP) that covers at least  3 years. The STIP should include a list of proposed projects that is  financially constrained—that is, projects that can be built with estimated  revenues. States must submit their proposed STIPs to FHWA and the  Federal Transit Administration for joint approval at least every 2 years;  however, the STIPs may be amended at any time, subject to federal  approval.
Some states also have policies or laws that direct the use of their funds.  These directives are taken into consideration when planning projects. For  example, Florida officials are concerned about the safety and preservation  of the current system. First, the state addresses safety in all their  transportation projects. Next, it is the state’s policy to preserve the existing  system before spending anything on new construction. In addition, Florida  law requires that at least 50 percent of the amount of new funds available  for capacity construction must go towards the state’s Intrastate system.  Also, in Arizona, according to a statewide agreement, 50 percent of the  funding available to the Arizona Department of Transportation must be  spent on state highway projects within the Phoenix and Tucson  metropolitan areas, and the remaining 50 percent must be spent on state  highway projects outside these two metropolitan areas.
To develop these planning documents and maintain their Interstate  highways, states use a variety of planning approaches. For example,  Florida has a complex system relying on policies, measurable objectives,  and performance monitoring to make its investment decisions. Florida  officials develop a 20-year long-range policy plan. Based on this 20-year  plan, they develop a 10-year program and resources plan containing  program funding levels given estimated revenues. Finally, the officials  develop and update annually a 5-year list of projects. To help select specific  projects that meet their goals, Florida officials use decision support  software to consider a multitude of data, including pavement condition  surveys, biennial bridge inspections, routine maintenance, safety data, and  analyses of congestion levels. Arizona is revising its long-term planning  process. In the meantime, Arizona is using an interim process to develop its  5-year construction program.
To identify states’ plans to meet Interstate needs over the next few years,  we asked states to provide information on the level of funding directed  toward the Interstates. Table 2 shows the amount states plan to spend in  2001 and the increases and decreases compared with 2001 throughout the 5  subsequent years. The states in bold indicate states included in our site  visits.
section_title: Tools for Addressing Congestion
paragraphs: States’ views differ on effectiveness of congestion relief tools. We surveyed  the states about the tools they were using to relieve congestion and the  tools’ usefulness. Although we identified below some of the tools  mentioned on our survey, based on our case study states, we found that  different tools may be more effective in one state than in another. For  example, adding lanes may be a useful tool to deal with congestion for  states with relatively low population density; however, this tool may not be  useful for states with relatively high population densities—particularly in  their urban areas, where the ability of adding lanes is limited since many  urban areas have the maximum number of lanes that will fit into available  space.
States reported using a variety of tools and varied in their assessment of the  tools’ usefulness. For example:  Increasing capacity through the addition of lanes. Forty-four states  indicated that adding lanes to increase capacity is very useful or  moderately useful.
Redesigning problematic highway sections. Three-fourths of the 52  states found redesigning highway sections to address traffic bottlenecks  to be very useful or moderately useful.
Using traffic incident management tools. About two-thirds of the state  departments of transportation stated that traffic incident management  tools (e.g., protocols for handling accidents) were very useful or  moderately useful.
Using technology for handling high-volume traffic—such as variable  message signs, ramp metering, and electronic tolls—42 states found  these to be useful.
Providing alternative transportation modes to reduce Interstate traffic  (e.g., buses, rail, and ferries)—12 states found these to be very useful or  moderately useful.
Providing incentives to drivers to reduce congestion. While 30 states  used these techniques—for example, reserving lanes for high-occupancy  vehicle and varying tolls by time of day—only 15 states believed them to  be very useful or moderately useful.
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