The U.S. transportation system makes possible a high level of personal mobility and freight activity for the nation's 284 million residents and nearly 7 million business establishments. In 2000, over 230 million motor vehicles, transit vehicles, railroad cars, and boats were available for use on the over 4 million miles of highways, railroads, and waterways that connect all parts of the United States, the fourth largest country in the world in land area. The transportation system also includes about 228,000 aircraft and over 19,000 public and private airports (an average of about 6 per county), and 440,000 miles of oil and gas transmission lines. This extensive transportation network supported an estimated 4.8 trillion passenger-miles of travel in 2000 and 3.8 trillion ton-miles of commercial freight shipments in 1999.
In general, the nation's transportation infrastructure has changed very little in recent years, while the number of vehicles has grown, in some cases dramatically. Road lane-miles, for instance, have grown by just 4 percent between 1980 and 2000, while cars and light trucks have increased by 40 percent. In air transportation, the number of aircraft operated by air carriers has increased by more than 35 percent since 1990, while the number of certificated airports (those serving scheduled air carrier operations with aircraft seating more than 30 passengers) has shrunk. The heavy use of the nation's infrastructure raises the specter of deterioration. Data show, however, the nation's roads, bridges, and airport runways, in general, improved in the 1990s.
As the level of traffic continues to climb and the amount of infrastructure remains the same, improved management of the system is one method being used to keep traffic flowing. The increasing use of information technology is important not only in commercial aviation, railroading, and waterborne commerce, but also in highway transportation, transit, general aviation, and boating. Information technology enhances the capability to monitor, analyze, and control infrastructure and vehicles and offers real-time information to system users. These technologies have a great deal of potential to help people and businesses use the transportation system more efficiently.
The widespread availability of a large variety of transportation options brings a high level of mobility to most of the nation's residents and businesses. Table 1, table 2, table 3, table 4, table 5 and table 6 provide a snapshot of the key elements of the U.S. transportation system.
To put the system into perspective, the system's 4 million miles of roads would circle the globe more than 157 times, its rail lines 7 times, and its oil and gas pipelines 56 times. The average distance traveled by a car or light truck annually (about 12,000 miles) equals a journey nearly halfway around the world, or added together, about one-tenth the distance to the nearest star outside our solar system.
The capacity of the air and transit systems in the United States is also phenomenal. There are more than enough seats on airplanes operated by U.S. air carriers to seat the entire population of Delaware (784,000 people). And the number of cars in the New York City subway system alone is more than large enough for the entire population of Baton Rouge, Louisiana (228,000 people), to have a seat at the same time.
From the telegraph used by railroads in the 19th century to radio and radar used in ships and planes at the beginning of the 20th century, information technology (IT) has enhanced the capabilities of our transportation systems. In recent years, these technologies have been integrated into all modes of transportation. Highway and transit applications of IT now are joining the other modes as new technology allows drivers to "navigate" roads.
Intelligent transportation systems (ITS) comprise a broad range of technologies, including those in the IT category, and help improve the efficiency, effectiveness, and safety of transportation. Travelers can obtain information and guidance from electronic surveillance, communications channels, and traffic analysis. ITS also boosts the capability to monitor, route, control, and manage information to facilitate travel.
The variety of technologies and approaches across the ITS spectrum, however, complicates assessments of the extent of their use. The U.S. Department of Transportation (DOT), Federal Highway Administration's ITS Joint Program Office conducts periodic surveys to gauge urban implementation in 75 metropolitan areas1 in the United States . The surveys collect data on deployment for nine ITS infrastructure components for highways, transit, and highway-rail grade crossings within the boundaries of metropolitan planning organizations (MPOs).
A single ITS component may use several technologies or approaches. For instance, electronic toll collection (ETC) technologies automatically collect payments through the application of in-vehicle, roadside, and communications technologies. About 73 percent of the metropolitan areas surveyed had toll collection lanes with ETC capacity in fiscal year (FY) 2000, up from 36 percent in FY 1997 .
Multiple ETC technology deployment highlights the growing importance of integrating ITS. Beyond measuring fixed ITS assets like vehicles, the ITS Joint Program Office also studies the integration among agencies operating the infrastructure. Federal officials define ITS integration as the transfer of information between three types of organizations: state departments of transportation, local governments, and transit agencies.
Traffic signal control and electronic toll collection are two of the top three highway ITS technologies currently being deployed (figure 1). These technologies directly benefit travelers by smoothing out trips on toll roads and signaled arterial roads. Highway-rail grade crossings have one of the lowest rates of deployment, but a major federal initiative is providing funds to address this area.
The Global Positioning System (GPS) is being used in all transportation modes (even walking), although to what overall extent is uncertain. Thirty-one percent of the metropolitan areas surveyed in 2000 showed some deployment of automatic vehicle location devices in fixed-route transit vehicles . GPS is not only used for commercial aviation, but also for general aviation. About 70 percent of corporate and over half of business-use aircraft have GPS devices, compared with about 40 percent of personal-use aircraft .
In 1996, the U.S. Coast Guard brought its Maritime Differential GPS (DGPS) online. Reference stations located every 200 miles along the coast and major rivers allow ships with the proper GPS receiving equipment to identify their positions within 5 to 10 meters, compared with 100 meters for other positioning systems. This is an important navigational aid, as some channels are less than 100 meters wide. The DOT is now implementing Nationwide DGPS to bring the same positioning accuracy to all parts of the continental United States and Alaska.
Railroads are developing positive train control (PTC) systems that will use nationwide DGPS to provide precise positioning information. PTC can prevent overspeed accidents and collisions between trains and between trains and maintenance-of-way crews. PTC can also improve the efficiency of railroad operations by reducing train over-the-road delays and increasing running time reliability, track capacity, and asset utilization. .
1. U.S. Department of Transportation, Federal Aviation Administration, General Aviation and Air Taxi Survey, 1996, available at http://api.hq.faa.gov/ga96/gatoc.htm, as of Dec. 5, 2000, table 7.2.
2. U.S. Department of Transportation, Federal Highway Administration, ITS Joint Program Office, ITS Deployment Tracking: 2000 Survey Results, available at http://www.itsdeployment2.ed.ornl/its2000, as of Oct. 31, 2002.
3. U.S. Department of Transportation, Federal Railroad Administration, "What Is Positive Train Control?" available at http://frarnd.volpe.dot.gov, as of Dec. 4, 2000.
Road building and widening continue to slowly increase the extent of the public road system and the length of lane-miles open to the public. Since 1980, miles of public road increased only about 2 percent, although, as a result of road widening, lane-miles increased nearly twice as much (3.8 percent). This small change in overall lane-miles masks growth in the higher elements of the roadway system. Between 1980 and 2000, Interstate lane-miles increased by 16 percent and principal arterials increased by 29 percent (figure 1; also see box on the Highway Functional Classification System) .
1. U.S. Department of Transportation, Federal Highway Administration, Highway Statistics (Washington, DC: Annual editions).
Between 1990 and 2000, the most noteworthy development in the U.S. highway vehicle fleet was the rapid growth in the number of registered light-duty trucks, including minivans, pickups, and sport utility vehicles (figure 1). During this period, the number of these vehicles grew from nearly 48 million to over 79 million, an increase of about 64 percent. This category now accounts for 35 percent of the total U.S. fleet, up from 25 percent in 1990. Fueled by the rapid increase in the number of light-duty trucks, the total U.S. fleet grew to nearly 226 million vehicles in 2000, a 17 percent increase over the 193 million vehicles registered in 1990 .
In contrast to the rapid and continual growth of light-duty trucks, the total number of cars and motorcycles in the fleet declined during the 1990s but by 2000 had regained their 1990 levels. Over the same period, the number of large trucks and buses increased at roughly the same rate as the total U.S. highway fleet, rising to just over 8 million large trucks and 746,000 buses by 2000. The 134 million cars in 2000 represent 59 percent of the total fleet, down from a 69 percent share in 1990 .
1. U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2000 (Washington, DC: 2001).
As a result of work underway, the travel time of high-speed intercity rail service may be reduced in half in the future using magnetic levitation (maglev) technology. A maglev system employs magnetic forces to lift, propel, and guide a vehicle over a guideway using state-of-the-art electric power and control systems.
Under the Transportation Equity Act for the 21st Century, the U.S. Congress created a national Magnetic Levitation Transportation Technology Deployment Program in the U.S. Department of Transportation (DOT). In May 1999, DOT's Federal Railroad Administration (FRA) gave planning funds to seven state maglev projects. These funds enabled the seven projects to compete for the second phase of deployment .
Of the seven projects, DOT selected two in January 2001 as the best positioned for early demonstration of the technology. One project would connect Baltimore, Maryland, and Washington, DC, along 40 miles of the Eastern Seaboard. The other project, the 54-mile Pennsylvania High-Speed Maglev Corridor, would link Pittsburgh International Airport to Pittsburgh and its eastern suburbs . Once this feasibility phase is completed, one of the projects will be eligible for $950 million for construction if Congress appropriates the funds.
Overall, FRA has provided $50.8 million through fiscal year 2002 for preconstruction planning for all seven projects (table 1). Just over half of these funds are supporting the two selected projects.
1. U.S. Department of Transportation, Federal Railroad Administration, "The Maglev Deployment Program," available at http://www.fra.dot.gov/o/hsgt/maglev.htm, as of Sept. 10, 2001.
2. _____. "U.S. Secretary of Transportation Slater Selects Two High Speed Maglev Projects," press release, Jan. 18, 2001, available at http://www.fra.dot.gov/o/hsgt/hot.htm, as of Sept. 17, 2001.
Urban transit is a complex mix of heavy, light, and commuter rail; buses and demand responsive vehicles; ferries; and other less prevalent types such as inclined planes, trolley buses, and automated guideways. This mode, measured by revenue vehicle-miles of service provided, grew by nearly 30 percent between 1991 and 2000 to over 3 billion miles. The U.S. population grew by 12 percent over this same period. The largest transit modes, bus and heavy rail, showed the slowest growth during this period (about 14 percent), while demand responsive transit grew the fastest (143 percent) (figure 1). Among rail modes, both light rail and commuter rail have seen substantial increases in service provided over this period, 90 percent and 25 percent, respectively .
Transit agencies in urbanized areas receive formula funding from the Federal Transit Administration for the purchase of vehicles. In fiscal year 2000, 152 agencies purchased 6,619 vehicles with formula funds. Most of the vehicles purchased (73 percent) were buses. Large urbanized area agencies purchased 69 percent of the buses (table 1) .
See box for Rural Transit.
1. U.S. Department of Transportation, Federal Transit Administration, National Transit Database, Annual years.
2. U.S. Department of Transportation, Federal Transit Administration, 2000 Statistical Summaries: FTA Grant Assistance Programs, "Table 91: Obligation of Flex Funds/FHWA Transfers, by Area/State (Fiscal Years 1992-2000)," available at http://www.fta.dot.gov/library/reference/statsum01/table19.html, as of Oct. 5, 2001.
The U.S.-flag oceangoing merchant fleet consisted of 421 operating vessels in 2002 (table 1). The total U.S.-flag commercial fleet operating in both foreign and domestic trades, however, consisted of 29,263 vessels. This does not include more than 5,000 tugs/towboats 1,500, other types of workboats (e.g., crewboats, supply boats, and utility vessels), or over 1,200 passenger vessels (table 2).
Over 98 percent of the total U.S.-flag commercial fleet operated in U.S. Domestic trade during 2000 (table 1). There are three major sectors of U.S. domestic trade: the inland waterways, Great Lakes, and domestic deep sea or coastwise trades. Barges operate primarily on the U.S. inland waterways and carry more than 90 percent of that tonnage . The Great Lakes fleet consists of self-propelled vessels and integrated tug/barge units. Most of these "Lakers" only carry cargo between the Great Lakes ports. Containerships and tankers operate in the U.S. domestic deep sea trade.
The Jones Act (Section 27 of the Merchant Marine Act of 1920) requires that maritime cargoes and passengers moving between U.S. ports be transported in vessels built and maintained in the United States, owned by American citizens, and crewed by U.S. mariners . As of April 2001, 157 privately owned, self-propelled vessels (of 1,000 gross tons and over) had unrestricted domestic trading privileges under the Jones Act (table 3).
1. U.S. Department of Transportation, Bureau of Transportation Statistics, Maritime Administration, and U.S. Coast Guard, Maritime Trade and Transportation 99, BTS99-02 (Washington, DC: 1999).
2. U.S. Department of Transportation, Maritime Administration, MARAD '99 (Washington, DC: May 2000).
U.S. ports that engage in foreign trade are facing key challenges such as waterfront congestion, port terminal productivity, and security needs. Nevertheless, U.S. foreign waterborne trade reached 1.2 billion metric tons in 2000, an increase of 2.4 percent over 1999 .
Landside access to water ports comprises a system of intermodal rail and truck services . Landside congestion, caused by inadequate control of truck traffic into and out of port terminals combined with the lack of adequate on-dock or near-dock rail access, affects the productivity of U.S. ports and the flow of U.S. international trade. Generally, productivity is difficult to measure. Cargo throughput can be used as a measure; however, it does not take into account the more efficient use of resources gained from capital investment .
The U.S. port industry has invested approximately $22 billion since 1946 on improvements in its facilities and infrastructure-about one-third of that total (approximately $6.4 billion) was invested between 1996 and 2000 (table 1). Investments include new construction and modernization/rehabilitation. In 2000, new construction accounted for two-thirds of total expenditures. After trailing in investments in the previous years, Atlantic ports accounted for 22 percent of total expenditures in 2000 . The Maritime Administration, U.S. Department of Transportation, expects that U.S. public ports will invest $9.4 billion between 2001 and 2005 .
Changes in vessel design impact access to both landside and waterside services. For example, container vessels have increased in size and capacity, which, in turn, drives a need for adequate transshipment hub and feeder ports.
The top ports in U.S. foreign trade are deep draft (with drafts of at least 40 feet) . Twenty-five U.S. ports received 73 percent of total vessel calls (table 2). Of vessels over 1,000 gross tons, tankers and containerships called at U.S. ports more often in 2000 than did other types of vessels.
The 2000/2001 U.S. economic slowdown detrimentally affected U.S. ports, particularly those on the West Coast. U.S imports declined from a 15 percent annual growth rate in early to mid-2000 to an estimated 6 percent drop during the first two quarters of 2001 .
1. DRI-WEFA, The U.S. Forecast Summary (Eddystone, PA: August 2001).
2. Robinson, Dolly, "Measures of Port Productivity and Container Terminal Design," Cargo Systems, April 1999.
3. U.S. Department of Transportation, The Maritime Transportation System: A Report to Congress (Washington, DC: 1999).
4. U.S. Department of Transportation, Maritime Administration, U.S. Foreign Waterborne Transportation Statistics 1999 & 2000, available at http://www.marad.dot.gov, as of Oct. 17, 2001.
5. _____. U.S. Port Development Expenditure Report (Washington, DC: December 2001).
In general, U.S. airport runway pavement is in good condition. When it is deteriorated, runway pavement can cause damage to aircraft turbines, propellers, and landing gear, and may result in runway closure. To prevent major problems, runway pavement requires regular maintenance to seal cracks and repair damage as well as a major overhaul every 15 to 20 years . The U.S. Department of Transportation, Federal Aviation Administration (FAA), inspects runways at public-use airports and classifies runway condition as good, fair, or poor (see table for definitions).
Airport runway quality improved from 1986 to 2000 (table 1). At the over 3,000 airports listed in the FAA's National Plan of Integrated Airport Systems (NPIAS), runways in fair or poor condition dropped from 39 percent in 1986 to 27 percent in 2000. Those in good condition rose from 61 percent to 73 percent. At commercial service airports, a subset of the NPIAS, only 2 percent of runways were in poor condition in 2000. Overall, commercial airport runways remain in better condition than other NPIAS airports.
As with highway systems, increasing runway extent and capacity can take many years. In 2001, expansion projects were in various stages of completion at 13 commercial service airports (table 2).
1. U.S. Department of Transportation, Federal Aviation Administration, National Plan of Integrated Airport Systems (1998-2002) (Washington, DC: 2000).
Overall, 40 percent of the nation's urban and rural roads were in good or very good condition in 2000, while 19 percent were mediocre or poor. The rest are in fair condition (table 1). The generally poorer condition of urban roads, as compared with rural roads, can be attributed to the higher levels of traffic they carry. Urban roads handled about 60 percent of all traffic in 2000 with far fewer miles of road. Indeed, on average in 2000, each lane-mile of urban road carried nearly 870,000 vehicles compared with about 170,000 vehicles by each lane-mile of rural road.
The condition of rural roads has generally improved since 1993, as have the higher level urban systems (figure 1). Miles of rural Interstates in poor or mediocre condition have declined from 35 percent to 14 percent, and miles of urban Interstates in poor or mediocre condition have declined from 42 percent to 30 percent. Rural and urban Interstates accounted for nearly one-quarter of all vehicle-miles traveled (vmt) in 2000. Miles of other freeways and expressways in urban areas (accounting for another 6 percent of all vmt) in poor or mediocre condition declined from 13 percent in 1993 to 11 percent in 2000.
Of concern in rural areas is the condition of major collectors, roads carrying about 8 percent of all vmt in 2000. The proportion of miles of these types of facilities in poor or mediocre condition increased from 19 percent to 22 percent between 1993 and 2000. In urban areas, the major concerns are other principal arterials that carried about 15 percent of total vmt in 2000 and minor arterials that carried another 12 percent. Over the same period, the proportion of other principal arterials in poor or mediocre condition increased from 23 percent to 30 percent while the proportion of minor arterials in that condition increased from 22 to 26 percent. The condition of urban collectors1 also deteriorated over this period, but these facilities carry much less traffic- about 5 percent of vmt in 2000.
See box for Highway Classification
1In both 1998 and 1999, the condition of about half the miles of urban minor arterials and about 40 percent of urban collectors were not reported.
The condition of bridges nationwide has improved markedly since 1990. Of the nearly 600,000 roadway bridges in 2000, 28 percent were found to be structurally deficient or functionally obsolete, an improvement of 31 percent since 1990. About 14 percent of all bridges were either structurally deficient or functionally obsolete in 2000 . Structurally deficient bridges are those that are restricted to light vehicles, require immediate rehabilitation to remain open, or are closed. Functionally obsolete bridges are those with deck geometry (e.g., lane width), load carrying capacity, clearance, or approach roadway alignment that no longer meet the criteria for the system of which the bridge is a part.1 In the 1990s, while the number of structurally deficient bridges steadily declined, the number of functionally obsolete bridges remained fairly constant (figure 1).
Overall, bridges in rural areas suffer more from structural deficiencies than functional obsolescence, whereas the reverse is true in urban areas (table 1). Nearly 22 percent of the bridges in rural areas that support local roads were structurally deficient and one-fifth of urban Interstate bridges were functionally obsolete in 2000. Nevertheless, a large number of both structurally deficient and functionally obsolete bridges support local roads in rural areas . Although the number of deficient bridges has declined nationwide, the experience of individual states varies widely. Between 1995 and 2000, the number of deficient and obsolete bridges increased in 13 states and the District of Columbia (see map).
1Structurally deficient bridges are counted separately from functionally obsolete bridges even though most structurally deficient bridges are, in fact, functionally obsolete.
1. U.S. Department of Transportation, Federal Highway Administration, Office of Engineering, Bridge Division, National Bridge Inventory database, available at http://www.fhwa.dot.gov/bridge/britab.htm, as of Sept. 27, 2001.