AASHTO’s Recommendations for the Interstate System of the Future
The Interstate Highway System for the 21st Century can be brought about through four strategic actions: preserve the current system, enhance its performance, expand capacity to meet future needs, and reduce growth in highway demand by expanding the capacity of transit and rail.
1. Preserve the Current System
The first priority will be to preserve the 47,000-mile system which has been built over the past 50 years so that it lasts for at least the next 50 years.
The Interstate System currently has approximately 210,000 lane-miles of pavement. As these pavement structures reach 40 to 50 years of life, the traditional approach of rehabilitation and resurfacing will no longer be sufficient and major portions of the Interstate System will need to have their pavements and foundations completely reconstructed. The Interstate System also has more than 55,000 bridges and tens of thousands of other significant structural elements, many of which are reaching 40 to 50 years of age. Bridges and other structures of this age usually require substantial rehabilitation, and, as we look out another 20 to 30 years, they will require complete replacement.
Though proper maintenance is essential to protect the massive national investments in the Interstate, public officials are often unaware of the magnitude of this responsibility. Capital investment in system preservation for both highways and bridges for the Interstate totaled $9.1 billion in 2002. It is important to ask, what level of investment will it take to preserve the Interstate System for the future? U.S. DOT’s 2004 Conditions and Performance Report estimated a “cost to improve” annual “constant dollar” investment for the next 20 years of $6.4 billion for rural and $24.9 billion for urban Interstates. Stated in “year of expenditure dollars” these numbers would be even higher.
As this reconstruction work goes forward, DOTs will have to minimize disruption to the traveling public. Work zone delays are estimated to cause 24 percent of non-recurring congestion. As the infrastructure ages and more rehabilitation is needed, we are going to have find better techniques to get the job done. Examples of these techniques include using components prefabricated off-site, longer-lasting materials, work at night, short-term shutdowns to allow intensive work, and incentives to get contractors to finish work faster.
2. Enhance System Performance
Advanced ITS technologies and better system management techniques need to be utilized to reduce congestion, improve throughput, and increase system reliability.
Capacity addition alone will not eliminate congestion or reliability problems. Traffic disruptions—crashes, breakdowns, construction work, weather, and special events—cause about 50 percent of delay. These disruptions can be addressed through aggressive system operations applications such as incident clearance, snow and ice control, and construction work zone management. Advanced technologies can be used to collect real-time information on road and travel conditions; improve travelers’ information; and use of ramp metering and lane management to improve traffic flow.
The decade-long effort to develop, demonstrate, and deploy ITS tools, architecture, and standards is starting to pay dividends. Electronic toll systems have reduced back-ups at toll booths, and truck electronic pre-clearance systems allow many trucks to bypass inspection stations altogether. 511 travelers’ information systems now serve 50 percent of the U.S. market.
Automobile manufacturers, technology suppliers, and government are collaborating on vehicle-to-vehicle and vehicle-to-system management communications technologies which will save lives and improve performance. An important part of the effort to improve system performance will be to build Interstate Systems of the future that work better because they have smarter technologies embedded in them.
The Interstate System is vulnerable to disruption from natural disasters and security-related incidents. The importance of the Interstate System in providing effective emergency response to such disruptions was dramatically illustrated in Gulf hurricane response over the past several years, and the response to 9/11 in Washington, DC, and New York.
There are several things which need to be done in the future to enable the Interstates to do an even better job. Funding assistance from the Department of Homeland Security is needed to protect critical infrastructure from terrorists attack and to improve surveillance and detection. Inter-agency communications capabilities need to be improved. And a joint program involving police, fire, and transportation agencies at the local and state level and justice, homeland security and transportation agencies at the Federal level needs to be developed to improve emergency response capabilities.
3. Expand Capacity to Meet Future Needs
To remain competitive in the global economy and meet America’s 21st Century mobility needs, we will need to add nearly as much capacity to the Interstate System in Phase II, as we did over the past 50 years in Phase I.
Since the 1950s, highway travel has increased from 600 billion VMT to 3 trillion, a five-fold increase. At the rates of growth projected by FHWA, VMT on U.S. highways will reach 7 trillion by 2055.The Interstate System carries 24 percent of all highway travel and 41 percent of truck freight travel, but it is getting harder to do so. During the past 50 years, mileage on the Interstate System has increased only 15 percent. Whatever redundancy and extra capacity that had been created when the system was originally built is being depleted. As has been noted by FHWA, by 2020, 90 percent of urban Interstates will be at or exceeding capacity.
Congestion on many segments of the Interstate System is bad and getting worse. Substantial capacity will have to be added to enable the Interstate System of the future to continue to play its role as a strategic national highway network with the ability to move traffic with acceptable speed and reliability.
As Neil Pedersen, Administrator of the Maryland State Highway Administration testified at the Commission’s November 16, 2006, hearing in New York, “AASHTO recommends that we initiate the next phase of development of the Interstate System which will add as much capacity in the future as we have built in the past.”
While state-by-state, in-depth analysis is needed to determine the future capacity needed, recent studies show that, if adequate funding were available, there is a need to add as many as 10,000 miles of new routes on new corridors, 20,000 miles of upgrades to National Highway System routes to Interstate standards, and 20,000 new lane-miles on existing Interstate routes. These could include exclusive truck lanes and value-priced lanes. System improvement would also include correcting bottlenecks, upgrading interchanges, improving intermodal connections, and the use of ITS technologies and advanced system management techniques to improve performance and safety.
Figure 20. Interstate Bottlenecks
Severe bottlenecks in metropolitan areas, many of which are located on the Interstate Highway System, impede the flow of commerce and contribute to significant delay for users of the system. (Figure 20.) At the same time, longer distance interstate and interregional traffic is often impeded by traffic congestion in metropolitan areas resulting from intraregional trips overwhelming available capacity. The Interstate System has almost 15,000 interchanges, many of which do not meet current operational and design standards and create significant traffic bottlenecks or safety problems. Some of the most significant congestion on the system is at major interchanges that were not designed to carry the volumes of traffic that currently use them. Higher projected future traffic volumes will exacerbate these problems.
Expansion of the Interstate System should be accomplished in conjunction with upgrades to connecting and local networks. Capacity improvements to National Highway System arterials which connect with the Interstate and other local arterials and collector routes will be needed for the network to function as efficiently as it needs to handle the future demand expected.
One of the key missions of the Interstate System when it was created in 1956 was to support national defense needs. With the end of the Cold War much of the military, which was forward-deployed in places like Germany and Korea, has been repositioned back here in the United States. However, the rapid response requirements of the military today are greater than ever before.
AASHTO recommends that the Commission call for a joint review by the Department of Defense, U.S. DOT and the states of what the Department of Defense requires in terms of support from highways, trucking, railroads, ports, and airports to meet its deployment and mobility needs and what changes and costs this will entail for the future.
4. Reduce Growth in Highway Demand by Expanding
the Capacity of
Transit
and Rail
Current trends show that peak-hour Interstate congestion in urban areas will increase from 29 percent of the system in 2000, to 46 percent by 2020, and that Interstate VMT will nearly double from 690 billion in 2006 to 1.3 trillion 20 years from now. We cannot afford either for congestion to get that bad or traffic to increase that much.
What is needed is a reduction in demand. Expanding the capacity of transit can help shift some local and regional trips off the Interstate and onto transit. Railroads must add capacity so they can continue to carry at least their current market share of freight, rather than shedding some of their share to trucking. Expanding the capacity of intercity passenger rail can help shift some long-distance trips off the Interstate and onto rail.
Commuting in America III, published by TRB in October 2006, shows that the share of commuters carried by transit decreased from 6.2 percent of the total in 1980, to 4.6 percent in 2000. This trend needs to be reversed and that transit ridership, which has grown to nearly 10 billion trips per year, should be doubled. To help make this possible, AASHTO supports policies that will assure that Federal funding for transit will increase at the same rate as Federal assistance for highways in the years ahead.
According to AASHTO’s 2003 Freight Rail Bottom Line Report, if sufficient public financial support was combined with private railroad investment, then the freight railroads would be able to hold on to their current market share of growing freight demand. This would avoid shedding freight from rail to trucks and reduce truck VMT by 15 billion over a 20-year period. Since 40 percent of truck VMT is carried on the Interstates this could be expected to reduce Interstate truck VMT by six billion.
AASHTO produced a report in 2002 entitled, Intercity Passenger Rail Transportation. That report found that, “Corridors with average speeds that are faster than driving can provide an effective alternative to both automobile and air service in markets between 100 and 500 miles.” Shifting demand from the Interstate to rail could help reduce highway congestion and more effectively use some airports if some short flights could be replaced with high-speed rail corridor service. A study of 21 corridors produced an estimate of $60 billion to make the short-term and long-term investments needed to make this intercity passenger rail service possible. That translated into an annual investment in 2002 dollars of $3 billion. Adjusting that figure to 2007 dollars would increase it to $3.3 billion annually.
Past Route Selection Process a Good Model for the Future
If the Commission, and later Congress, concur that today’s 47,000-mile Interstate System needs to expand significantly to meet future needs, the process by which the routes for the original Interstate System were selected as well as the process by which the routes for the National Highway System (NHS) were selected in the 1990s should be reviewed. They appear to be a model for how we should proceed in the future.
In December 1944, Congress passed the Federal-Aid Highway Act which authorized a 40,000-mile system of Interstate roads. The Bureau of Public Roads, the American Association of State Highway Officials (AASHO), and the states then began a joint effort to determine the specific routes for the new system. In 1947, a report was issued showing the general location of an Interstate System of 37,700 miles including 2,900 miles in urban areas with the remaining miles reserved for additional urban routes. The Bureau of Public Roads and the State Highway Departments, in cooperation with cities and counties, worked on this and in late 1955 developed a series of “yellow books” which showed the location of the remaining urban mileage that had been held in reserve in 1947.
When the Bureau of Public Roads shared these “yellow books” which indicated Congressional District by District where the urban mileage would go, this helped build the final support needed to pass the Interstate program in 1956.
The 40,000-mile system, later expanded to 47,000 miles, came about not as something designated at the Federal level, but designed through an extended process of Federal–state cooperation and consultation at the grass-roots level with counties, cities, state legislators, and community interest groups all of whose views had to be taken into consideration in deciding on specific alignments.
The process for designation of the routes on the National Highway System approved by Congress in 1995 was also instructive. During the 1980s, FHWA and the states through AASHTO explored the concept of creating a National Highway System. In 1989, FHWA and AASHTO agreed to undertake a joint effort to define and map a national highway system that would be a major element in a post-Interstate highway system. They later agreed with the Office of Management and Budget to test three mileage levels ranging from 120,000 miles to greater than 150,000 miles. Passage of ISTEA in 1991 required FHWA to formally work with the states to define an NHS of 155,000 miles plus or minus 15 percent and submit this to Congress by December 1993, for formal Congressional approval.
FHWA and the states were joined by the MPOs in the designation of routes in metropolitan areas. A series of maps recommending NHS routes in metropolitan areas were transmitted to Congress in 1994. The National Highway System Designation Act was passed and signed by the President in November 1995.
In both the case of the Interstate System and the NHS, Congress established a mileage target for the system and policies outlining the characteristics of the system desired. The specific route alignments were determined at the state and local level and then coordinated at the multi-state level and finalized through a joint effort of the Federal highway agency, AASHTO, and the states.
