Sixty years ago the nation embarked on its greatest public works project, the construction of the Interstate Highway System. President Dwight D. Eisenhower provided strong support for the building of an Interstate Highway System that would improve traffic safety, reduce travel times and improve the nation’s economic productivity.
Serving as the most critical transportation link in the nation’s economy, the Interstate Highway System has significantly improved the lives of U.S. residents and visitors. Throughout the nation, the Interstate system allows for high levels of mobility by greatly reducing travel times and providing a significantly higher level of traffic safety than other routes.
But 60 years after President Eisenhower articulated a vision for the nation’s transportation system, the U. S. again faces a challenge in modernizing its aging and increasingly congested Interstate highway system. If Americans are to continue to enjoy their current level of personal and commercial mobility on Interstate highways and bridges, the nation will need to make a commitment to identifying a long-term funding source to support a well-maintained Interstate Highway System able to meet the nation’s need for additional mobility.
In this report, TRIP looks at the history and benefits of the Interstate Highway System, its current use and condition, and the future needs of the nation’s most critical transportation system. Sources of data for the report include the U.S. Department of Transportation (USDOT), the Federal Highway Administration (FHWA), the National Highway Traffic Safety Administration (NHTSA), and the U.S. Census Bureau. State-by-state Interstate data can be found in the Appendix. The major findings of the report include the following.
The Dwight D. Eisenhower National System of Interstate and Defense Highways, which has been called the most ambitious public works project built since the Roman Empire, is the most critical link in the nation’s transportation system.
- The Interstate Highway System, which includes 2.5 percent of all roadway lane miles in the U.S., carries 25 percent of all vehicle travel in the nation.
- Since funding of the Interstate system was approved in 1956, annual vehicle miles of travel in the U.S. have increased by 387 percent, from 626 billion miles driven, to approximately three trillion miles driven.
- Since 1956, the number of vehicles in the nation has increased by 300 percent, from 65 million vehicles to 260 million vehicles and the nation’s population has increased by 91 percent, from 168 million to 321 million.
The 47,662-mile Interstate Highway System includes 10 transcontinental routes and highways varying in length from 18 miles to more than 3,000 miles.
- The Interstate Highway System includes three east-west transcontinental routes: Interstate 10 from Los Angeles to Jacksonville; Interstate 80 from San Francisco to Teaneck, New Jersey; and Interstate 90 from Seattle to Boston.
- The Interstate system includes seven north-south transcontinental routes: Interstate 5 from San Diego to Blaine, Washington; Interstate 15 from San Diego to Sweetgrass, Montana; Interstate 35 from Laredo, Texas to Duluth, Minnesota; Interstate 55 from New Orleans to Chicago; Interstate 65 from Mobile, Alabama to Gary, Indiana; Interstate 75 from Miami to Sault Ste. Marie, Michigan; and Interstate 95 from Miami to Houlton, Maine.
- The longest Interstate route, excluding three-digit urban routes, is Interstate 90 from Seattle to Boston, which is 3,021 miles in length.
- The shortest Interstate route, excluding three-digit urban routes, is Interstate 97 in Maryland, running 18 miles from Annapolis to Baltimore.
The U.S. Department of Transportation has determined that the nation faces a significant backlog in needed Interstate highway repairs and improvements, and at current investment levels traffic congestion on the nation’s Interstate Highway System is likely to increase.
- The current backlog of needed improvements on the nation’s Interstate Highway System is estimated by the U.S. Department of Transportation to be $189 billion.
- The backlog on the nation’s Interstate Highway System includes $59 billion needed to improve pavement conditions, $30 billion to improve bridges and $100 billion for needed system expansion and enhancement.
- The U.S. DOT report also found that the U.S. is only spending approximately 61 percent of the amount needed annually to make needed repairs and improvements on the Interstate Highway System to keep the system in a state of good repair and provide adequate capacity to meet growing personal and freight mobility needs.
- Annual spending on the nation’s Interstate Highway System is estimated to be $20.2 billion, while approximately $33 billion annually is needed to complete Interstate repairs and improvements needed to maintain Interstate highways and bridges and to relieve traffic congestion.
The primary source of revenue for the Interstate Highway System is the federal surface transportation program, which was authorized in 2015 through 2020. The program includes modest funding increases and provides states with greater funding certainty, but falls far short of providing the level of funding needed to meet the nation’s highway and transit needs. The program does not have a long-term and sustainable revenue source.
- Signed into law in December 2015, the Fixing America’s Surface Transportation (FAST Act), provides modest increases in federal highway and transit spending, allows states greater long-term funding certainty and streamlines the federal project approval process.
- The five-year, $305 billion FAST Act will provide a boost of approximately15 percent in highway funding and an 18 percent boost in transit funding over the duration of the program, which expires in 2020.
- While the modest funding increase and certainty provided by the FAST Act are a step in the right direction, the funding falls far short of the level needed to improve conditions and meet the nation’s mobility needs, and fails to deliver a sustainable, long-term source of revenue for the federal Highway Trust Fund.
- In addition to federal motor fuel tax revenues, the FAST Act will be funded by $70 billion in U.S. general funds, which will rely on offsets from several unrelated federal programs including the Strategic Petroleum Reserve, the Federal Reserve and U.S. Customs.
- Revenue collected from the 18.4 cents-per-gallon federal motor fuel tax and the 24.4 cents-per-gallon federal diesel fuel tax are the primary sources of funding for the federal Highway Trust Fund, which distributes funds to state and local governments for highway and bridge repairs as well as other surface transportation improvements, including public transit, pedestrian and bicycling facilities.
- Highway Trust Fund revenues have not been adequate to support federal surface transportation spending since 2008. As a result, Congress has approved seven pieces of legislation transferring a total $143 billion in borrowed or General Fund revenue into the Highway Trust Fund.
- When the FAST Act expires at the end of FY 2020, the Congressional Budget Office projects the average annual shortfall to the federal Highway Trust Fund will grow to $16 billion.
- If Congress decides to provide additional revenues into the federal Highway Trust Fund, a number of technically feasible revenue options have been identified by the American Association of State Highway and Transportation Officials.
Founded in 1971, TRIP ® of Washington, DC, is a nonprofit organization that researches, evaluates and distributes economic and technical data on surface transportation issues. TRIP is sponsored by insurance companies, equipment manufacturers, distributors and suppliers; businesses involved in highway and transit engineering and construction; labor unions; and organizations concerned with efficient and safe surface transportation.