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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - July/August 2000

Highways and Bridges on The Brink of The New Century

by Clifford Comeau and David Smallen
One in seven bridges in the United States is functionally obsolete. Functionally obsolete bridges are those that do not have adequate lane widths, shoulder widths, or vertical clearances to serve the traffic demand or those that may be occasionally flooded

During the 1990s, lawmakers decided to channel more money into the nation’s highways and bridges — a policy that has now begun to pay off with better pavement, improved bridges, and higher levels of safety.

With more money flowing into the Highway Trust Fund and back out to the states and metropolitan planning organizations, the new 1999 Status of the Nation’s Highways, Bridges, and Transit: Conditions and Performance envisions a time when transportation planners will be able to shift from maintaining the system’s performance to improving it. While the overall system may be performing well, officials of the Federal Highway Administration (FHWA) and others continue to wrestle with how to make it better — in particular, how to reduce the safety risk to all travelers. From a reporting perspective — one that could have a major impact on future policies and investment decisions — they are trying to come to grips with the thorny problem of how to measure congestion.

Officials see a slowing of the long-term growth in vehicle-miles traveled (VMT), reflecting the limits on how much more people can drive.

FHWA sends Conditions and Performance to Congress every two years, as required by law, to give lawmakers a snapshot of how well the status of the system matches the funds being invested and how much additional money will be needed in the future to reach varying levels of performance. It also provides a look at major long-term trends in the use of the nation’s highways and bridges.

In recent years, FHWA has expanded the report’s scope to provider a fuller view of the highway transportation system. The 1999 report includes a safety chapter. The inclusion of this chapter demonstrates the Department of Transportation’s commitment to safety — the department’s top priority.


The record highway funding levels authorized by the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) and the Transportation Equity Act for the 21st Century (TEA-21) in 1998 are being felt throughout the system. More construction funding has produced interstate highway pavements that are generally better — especially in rural areas — with fewer deficient bridges.

The percentage of "poor pavement" on rural interstate highways has been cut from 5.7 percent to 3.7 percent since the 1997 report.

In general, conditions are worse in urban areas where more than 9 percent of the interstate highways are rated as poor. But even this rate reflects a slight improvement from the 1997 level.

On all rural roads, the percentage of roads with poor pavement was cut from 8 percent to 5.5 percent from 1993 to 1997, while the percentage of all urban roads with poor pavement dropped from 10.5 percent to 9.3 percent. The trend in urban areas has reversed, however, with a higher percentage of poor pavement since 1995.

Pavement quality is generally better in rural areas than in urban areas for all categories of roads, and it is improving faster — significantly faster on interstates and on minor arterials. Urban interstates had a 5-percentage point drop in pavement rated "good" or "very good."

From 1997 to 1999, the percentage of all urban roads with poor pavement dropped from 10.5 percent to 9.3 percent.

Fewer than three in 10 of the nation’s bridges are rated as "deficient" — either structurally deficient or functionally obsolete — down from 35 percent since 1992. Most bridges that are structurally deficient are not in danger of falling down, but they are likely to be load-posted so that heavier trucks will be required to take an alternative, longer route. Functionally obsolete bridges are those that do not have adequate lane widths, shoulder widths, or vertical clearances to serve the traffic demand or those that may be occasionally flooded.

On the Interstate Highway System, one in five bridges is deficient, declining from 25.3 percent in 1992. On rural interstates, one in six bridges is deficient, and on urban interstates, one in four is deficient.

Since 1992, significant progress has been made in eliminating structurally deficient bridges. One in six bridges is structurally deficient, compared to one in five in 1992.

A lesser percentage — one in seven — is functionally obsolete, but less progress has been made. On the Interstate System, three times as many bridges are functionally obsolete as are structurally deficient.

Of all road systems, rural interstates have the lowest percentage of deficient bridges — one in seven. Urban minor arterials and collectors have the highest — almost two in five.

Overall, on all types of roads, urban bridges are more likely to be deficient than rural bridges.

Different levels of government face different bridge problems. The federal government has fewer deficient bridges — less than one in four — than state governments — one in four — who, in turn, have fewer deficient bridges than local governments — one in three. Most federal and state deficient bridges are structurally obsolete, but almost two-thirds of local deficient bridges are structurally deficient. State and local governments each own about half of the nation’s bridges, and the federal government owns less than 2 percent.

More construction funding, authorized by the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) and the Transportation Equity Act for the 21st Century (TEA-21) in 1998, has resulted in the improvement of many highways. With generally better pavements and increased capacity, the new or improved highways are safer, and traffic flows more smoothly.


In 10 years, the fatality rate and the injury rate on the nation’s roads have dropped markedly.

The fatality rate dropped below two for every 100 million vehicle-miles traveled (VMT) in 1991 and has continued a steady decline to 1.6. This decline continues a long-term trend from 5.3 deaths per 100 million VMT in 1967 to 3.3 in 1977 to 2.4 in 1987.

The injury rate dropped from 169 per 100 million VMT in 1987 to 131 in 1997. Officials credit the drop to a combination of tougher laws with stronger enforcement and educational campaigns on seat belt use, alcohol-impaired driving, air bags and child restraints, and safety-related highway improvements. They cite better traffic signs and pavement markings, traffic signals, guardrails, median barriers, roadway lighting, skid-resistant pavement, and controls at highway-rail grade crossings.

While the death and injury rates have dropped, the spurt in traffic during the 1990s has reversed the decline in the actual number of people killed. From a low of 39,250 deaths in 1992, the number climbed back to more than 42,000 in both 1996 and 1997.

The Department of Transportation (DOT) is targeting efforts to reduce pedestrian fatalities, which account for more than one in eight of all deaths. The effort will include better pedestrian facilities, including sidewalks, clearly marked crosswalks, and improved barriers.

DOT will also test new approaches to speed management. Speed contributes to one-third of all fatal crashes or about 13,000 deaths. Three states are testing "variable speed limits" that will adjust speed limits to weather. Advanced technology will also be used to crack down on speeders, red-light runners, and other aggressive drivers.

A one-fifth rise in deaths from large truck crashes since 1992 has focused attention on motor carrier safety. To reverse the trend, Secretary of Transportation Rodney E. Slater set a goal last year to reduce fatalities from big truck crashes by 50 percent in 10 years. The goal is part of a Commercial Motor Vehicle Safety Action Plan.

The widespread deployment of crash-avoidance devices in trucking fleets will be on the forefront of the

Because pedestrian fatalities account for more than one in eight traffic-related deaths, the Department of Transportation is promoting better pedestrian facilities, including sidewalks, clearly marked crosswalks, and improved barriers.

effort to reduce truck crashes. Intelligent Transportation Systems (ITS) safety technologies that warn drivers of potential crashes, warn them when they are drifting out of their lane, and ensure a continual safe distance between vehicles offer great promise for significantly reducing the number of crashes.

Transportation officials will also be targeting safety initiatives to teenagers and senior citizens, the two age groups with the highest fatality rates. Teenagers could be subject to new, graduated licensing systems in as many as 20 states, and they will be the focus of new drunken driving campaigns

In 1997, men over the age of 85 had a traffic fatality rate nearly 10 times that of the general population.

Senior citizens are a source of concern for policy-makers. Aged people are a growing segment of the nation’s population, and a workable solution to their high traffic fatality rate is not clear. In 1997, men over the age of 85 had a traffic fatality rate nearly 10 times that of the general population.

Seat belts, air bags, and the campaign against alcohol-impaired driving were the three major safety success stories of the 1990s. In 1997, seat belts were used by four of five people in the 13 states with primary enforcement laws allowing police to stop a car for a seat belt violation. In the 36 other states that only allow police to enforce seat belt laws if a car is stopped for another offense, three of five people wore them.

The National Highway Traffic Safety Administration estimates that air bags saved nearly 2,300 lives in the decade ending in 1997, with 842 lives saved in 1997 alone.

Alcohol-related deaths were cut from 25,000 in 1982, two years before the enactment of the 21-year-old minimum drinking age, to 16,000 in 1997 — a 35-percent drop.

Investing in Highways

A bigger share of highway money is being used for capital costs, while highway spending continues to outpace inflation. In addition, there has been a shift in focus from investment in new roads and bridges to system preservation and enhancement.

Almost half of all 1997 highway investment was used for capital outlays. This was the biggest share since 1980 and a continuation of a steady increase that started in 1993. About one-fourth of expenditures are used for routine maintenance and traffic services, including traffic control systems, toll collection, snow removal, beautification, and air quality monitoring.

Other non-capital expenditures, such as law enforcement, administration, research, and interest payments, make up about one-fifth of all highway spending. Funding for highway law enforcement and safety programs is the fastest growing part, rising by more than 13 percent from 1995 to 1997.

Since 1981, highway spending has grown faster than inflation. When adjusted for inflation, highway spending reached an all-time high in 1996. However, while the number of vehicle-miles traveled is growing, a reduction in spending for maintenance and other items has led to a 7-percent drop in inflation-adjusted total highway spending per VMT since 1982 even though capital spending has risen by 8 percent.

In 1997, reflecting the shift in investment strategy, almost half of all capital outlay — $23 billion — was invested in system preservation apart from $26 billion spent on maintenance and traffic services. Almost $8 billion was spent on new roads and bridges, and an additional $14 billion was used for adding lanes to existing roads.

States used their new flexibility under ISTEA during the early 1990s to shift funds from capacity expansion to system preservation and other improvements. The shift was slightly reversed in the 1995 to 1997 period. Spending on system preservation and system enhancement still remains higher than the 1993 levels and is expected to continue to grow. FHWA attributes the slight change from 1995 to 1997 to a decline in bridge preservation spending, but this is not seen as the start of a new trend.

Funding for the Future

The increased highway and bridge spending of the past decade has narrowed the gap with investment requirements cited in previous reports. The gap is expected to decline even further in the future as spending under TEA-21 rises.

FHWA estimates that $57 billion will be needed annually to maintain the highway and bridge system conditions. The largest single need would be for urban interstate highways, which will require $10 billion.

The cost to improve highways and bridges is estimated at $94 billion with more than half the funds devoted to system preservation.

The gap between current investment and the cost to maintain highway and bridge conditions narrowed by more than one-fourth from 1995 to 1997 to $8 billion and is projected to drop to $3 billion per year through 2003.

Higher spending has also narrowed the gap with the total of all economically justifiable highway and bridge investments (called Maximum Economic Investment). In 1995, the investment needs were double the existing spending. The gap narrowed by 14 percent in 1997 — to $45.3 billion — and is projected to drop to $45 billion per year through 2003, three-fourths of the projected spending.

The higher spending levels are, for the first time, allowing officials to project that the gap between available funds and the cost to maintain will be closed in 2003, the last year that TEA-21 will be in effect.

"Combined highway capital spending by all levels of government is projected to reach $56.5 billion in 2003. This is virtually identical to the $56.6 billion average annual cost to maintain highways and bridges," according to Conditions and Performance.

If spending continues to rise at the same rate after TEA-21, capital investment is likely to exceed the cost to maintain highways and bridges. If the spending increases occur as projected, transportation officials around the country would then have additional funds to select projects for improvement of the highway and bridge system. Almost three-fourths of the highway investment backlog is in urban areas.


Congestion is a growing problem in virtually all urban and suburban areas. The Texas Transportation Institute estimated that travel under severe or extreme congested conditions doubled from 1982 to 1997 — from 14 percent to 36 percent — costing $72 billion in wasted fuel and time.

FHWA officials are continuing to search for a way to measure congestion, a major indicator of how the highway system is performing.

"Congestion, an easy concept to understand, is actually problematic to measure," the report states. Part of the problem is that people in different cities have varying perceptions of congestion.

FHWA looked at three different ways to measure congestion for the report and then sought out a university transportation center for another study of congestion. The three means of measurement are:

  • Daily vehicle-miles of travel (DVMT). Based on actual traffic counts, this measure shows that the volume of travel per lane-mile has increased throughout the system for the past years — 2 percent annually in urban areas, 3.4 percent in rural areas.
  • Volume/service flow (V/SF). This calculation measures the severity of congestion by comparing peak-hour traffic to the theoretical capacity of the highway. If the volume exceeds 80 percent of capacity, the road is considered to be congested. More than half of all peak-hour traffic on urban interstates is under congested conditions.
  • Delay. Based on modeling, delay measures the difference between estimated travel speed and free-flow travel speed. It extends the measure of congestion throughout the day instead of limiting it to peak hours. The models showed that delay declined from 1995 to 1997, and on urban interstates, delay fell below 1993 levels. The greatest delays are on principal arterials in urbanized areas of more than 200,000 people. These roads are taking the brunt of metropolitan area growth. Delay is rising on all rural road categories.

In their study of congestion, the Texas Transportation Institute (TTI) estimated the costs of congestion annually in 68 urbanized areas by reviewing daily traffic volume per lane. TTI estimated that travel under congested conditions doubled from 1982 to 1997, costing $72 billion in wasted fuel and time. Travel in severe or extreme congested conditions grew from 14 percent in 1982 to 36 percent in 1997, according to TTI.

Changes in driving behavior have produced a change in the way congestion is measured. Drivers in the late 1990s were moving at faster speeds with less space between vehicles, leading technicians to determine that highways with the same traffic volume as 15 years earlier would no longer be classified as congested. Researchers are still seeking an "inexpensive and reliable" method of determining delay.


In general, both pavement and bridge conditions have improved over the past decade. Safety on our highways has improved significantly, but there is still room for further improvement. Congestion is still a problem, especially in the larger urban areas. Funding for highways has increased under TEA-21 and may approach the point where pavement and bridge conditions can be maintained along with cost/beneficial capacity improvements.

Clifford Comeau is the leader of the Highway Needs and Investment Analysis Team within FHWA’s Office of Legislation and Strategic Planning. He manages the development of the biennial report to the Congress, Status of the Nation’s Highways, Bridges, and Transit: Conditions and Performance. His career has included assignments in federal-aid, design, construction, planning, and policy. He has a bachelor’s degree in civil engineering from North Carolina State University, is a registered professional engineer in Michigan, and is a member of the American Society of Civil Engineers.

David Smallen is the president and chief executive officer of David Smallen Associates, a consulting/writing/editing company in Washington, D.C. For 14 years, he served on Capitol Hill, starting as press secretary and then as director of communications for the House Committee on Public Works and Transportation and as senior staff member of the House Subcommittee on Investigations and Oversight. Before that, he was a newspaper and news service reporter. He has a bachelor’s degree from Duke University, and he attended the graduate school of journalism at the University of North Carolina.