From 1990 through 2005, the total population in the United States grew by approximately 40 million to nearly 300 million people.1 Concurrent with the population growth were even faster increases in travel. According to the U.S. Bureau of Transportation Statistics (BTS), travel increased across almost every transportation mode during the last 15 years, sometimes at rates greater than the overall population growth.2
Most people in the United States rely on motor vehicles for mobility, accounting for 88 percent of overall travel.3 It is not surprising then, that much of the increase in travel has occurred on the nation's highways. Now, more people are traveling more miles on the nation's highways than at any point in our history. The Federal Highway Administration (FHWA) estimates that, in 2004, motor vehicles traveled more than 2.9 trillion miles on U.S. highways, up from 2.85 trillion miles traveled in 2002.4 Vehicle miles traveled increased by 35 percent from 1990 to 2003 and by 161 percent from 1970 through 2003.
Travel by mass transit has also increased. According to BTS, the passenger miles traveled on mass transit from 1990 to 2003 increased by nearly 15 percent.5 Since 1995, transit use has increased by 23 percent, a rate higher than highway travel.6 Cambridge Systematics reports that demand for public transportation is at its highest point since World War II. Passengers now make 9.5 billion trips by public transportation each year.7
In addition to individual travel, a substantial growth in freight movement will continue to place greater demands on the surface transportation network. According to a report by the Hudson Institute, in 2000, well over 12 billion tons of goods worth roughly $10 trillion moved through the U.S. freight system (not including pipelines).8 FHWA estimates that by 2020, the volume of freight movement in the United States may double.9 Although some of the expected freight movement increases can be traced to domestic production, growth in international trade will probably have the most significant influence.
Economic growth in Asia, most notably China, the NAFTA agreement, the widening of the Panama Canal and the development of trade corridors from Latin America through Canada, will increase freight movement in the United States. Experts predict that trade between the United States and Asia is likely to double over today's rates to more than 700 million tons of freight by 2020. Similarly, trade between the United States and South America will likely increase to 600 million tons of freight by 2020, up from less than 300 million tons of freight in 1998.10
Freight growth has a direct effect on the use of the national transportation system. More freight means more demand for trucks, trains, barges and planes to transport the goods. The Hudson Institute report estimates that, under current scenarios, by 2020, freight growth will increase trucking-ton miles by 64 percent, increase rail-ton miles by 49 percent, increase barge traffic by 15 percent, and double the demand for air freight.
The greatest effects of freight growth may be on truck use and the highway system. The majority of freight travels by truck in the United States, and since 1990, the demand for trucking has grown at an annual rate of nearly 4 percent.11 Under current scenarios, U.S. truck traffic connected to international trade is expected to double between 2002 and 2015 from 3.8 billion vehicle miles traveled to 7 billion vehicle miles traveled.12 If other transportation modes are insufficiently supported, however, an even greater burden for freight transport will shift to the trucking industry and, ultimately to the highways.
There are indications that trains and barges may have difficulty meeting the growing demands for freight movement. Since 1980, the physical infrastructure needed to support freight rail traffic has steadily diminished. The number of miles of track has dropped by approximately 37 percent.13 Moreover, a significant portion of the rail network, built in the 1800s, was designed for east-west traffic and to facilitate travel between hubs.14 Infrastructure in many locations, particularly bridges and tunnels, is in disrepair. In addition, some rail tunnels may lack the necessary height clearances for double-stacked freight boxes.15 Many rail terminals are located in dense urban areas with little room for expansion. Where facilities have been developed away from urban centers, they often lack the good roads necessary to make their use most efficient.16 Some turnaround has occurred in this trend during the last five years as railroads have seen an increase in profitability and have committed more resources to infrastructure investment. For example, BNSF reports that it now spends over $1 billion every year on railroad maintenance.17 Nonetheless, railroads still face an enormous challenge.
Similarly, water freight operations may face infrastructure challenges that make it difficult meet growing demands. Barges transport approximately 20 percent of the nation's coal and 60 percent of the nation's grain.18 Many inland waterways that support barge travel need to be modernized. The U.S. Army Corps of Engineers reported in 1997 that the median age of locks on inland waterways was 37 years, and that locking delays averaged six hours.19 Without sufficient investment in water and rail infrastructure, an even greater burden for freight traffic may be shifted to trucks and to the nation's highways, roads and bridges.