Chapter 1 - Summary

Chapter 1 - Summary

In this edition of the Transportation Statistics Annual Report, the Bureau of Transportation Statistics (BTS) of the U.S. Department of Transportation, Research and Innovative Technology Administration (RITA), focuses on transportation indicators related to 15 specific topics (chapter 2) and on the state of transportation statistics (chapter 3).

Summary of Transportation Indicators (Chapter 2)

Chapter 2 contains transportation data and information on the following topics:1

1. traffic flows (B),
2. the condition of the transportation system (K),
3. accidents (I),
4. variables influencing traveling behavior (E),
5. travel times (C),
6. availability of mass transit and number of passengers served (G),
7. travel costs of intracity commuting and intercity trips (F),
8. productivity in the transportation sector (A),
9. transportation and economic growth,
10. government transportation finance,
11. transportation-related variables that influence global competitiveness (L),
12. frequency of vehicle and transportation facility repairs and other interruptions of transportation service (H),
13. vehicle weights (D),
14. transportation energy, and
15. collateral damage to the human and natural environment (J).

Each of these topics is represented by a series of key indicators in chapter 2. The indicators are presented graphically along with analyses; supporting data tables are in appendix B (box 1).

1. Traffic Flows

Tracking the volume and geographic flow of traffic on America 's roads, rails, and waterways and at airports helps to ensure that transportation infrastructure is properly maintained and has adequate capacity to meet demand. Data on traffic flows also help to evaluate congestion trends by mode or a combination of modes and the potential for shifts in traffic within the route structure of a particular mode and from one mode to another. Aggregate traffic flow data, used to evaluate trends over time, can be helpful in measuring transportation-related safety and environmental trends.

Passenger and freight flows are measured in a variety of ways (figure 1). Vehicle-miles of travel (vmt) for both passenger and freight are calculated by multiplying the number of vehicles by miles of travel. Passenger travel can also be measured by estimating the number of miles traveled per person for each mode. This method takes into account not only the distance traveled by a vehicle but also the number of people in the vehicle. In addition to vmt, freight flows are measured in ton-miles-the movement of one ton of cargo one mile. Each of these measurements allows for comparisons across modes and between passenger and freight traffic, although these comparisons are affected by data-collection methods and definitions.

Passenger-miles of travel (pmt) in the United States totaled an estimated 5.0 trillion in 2002, or about 17,000 miles for every man, woman, and child (box 2). Over the decade 1992 to 2002, pmt increased 27 percent. Almost 86 percent of pmt in 2002 was in personal vehicles (passenger cars and light trucks, which include sport utility vehicles (SUVs), pickup trucks, and minivans). Air carriers accounted for another 10 percent of pmt.

Trucking moved the majority of freight by tonnage and by shipment value in 2002: 9.2 billon tons (58 percent of the total tonnage) and $6,660 billion (64 percent of the total value). There were 15.8 billion tons of commodities shipped in 2002 (up 18 percent since 1993) at a value of $10.5 trillion (in chained 2000 dollars),2 up 46 percent since 1993. These data are preliminary Commodity Flow Survey (CFS) estimates augmented by supplemental data, providing a more complete accounting of the Nation's goods movements.3 An alternative methodology, developed by BTS using a variety of data sources, estimates that freight transportation generated 4.4 trillion domestic ton-miles in 2002, 18 percent more than in 1992 (box 3).

Highway passenger vmt dominates total highway vmt and amounted to 2.9 trillion in 2003, up 26 percent since 1993. Meanwhile, domestic service air carrier (aircraft) vmt rose 46 percent to total 6.1 billion in 2003. Freight highway vmt totaled 215.9 billion in 2003, a 35 percent increase since 1993.

In addition to studying freight and passenger volumes, it is also important to track changes in the geographic and modal distribution of freight and passenger travel in order to anticipate and alleviate areas of high congestion and for other purposes. Truck, rail, air, and waterborne freight flow maps help planners pinpoint potential problem areas in the transportation system. (figure 2).

2. Condition of the Transportation System

Two major components of the transportation system-vehicles and infrastructure-are prone to deterioration due to wear, aging, and damage. Measures of the net capital stock of the transportation system-the value in dollars of vehicles, infrastructure, and other components-provide comprehensive indicators that combine system condition (quality) with capacity (quantity) and allow for comparisons across modes.

Highway-related capital stock (highway infrastructure, consumer motor vehicles, and commercial trucks) represented the majority ($2,917 billion in chained 2000 dollars) of the nation's transportation capital stock in 2003, rising 38 percent since 1993. The combined value of privately owned capital stock ($609 billion in 2003) for other individual modes of the transportation system, including rail, water, air, and pipeline, is less than the value of consumer motor vehicles alone ($1,325 billion). The only mode with declining values during the period was railroad transportation (down 6 percent). BTS has been developing data on airports, waterways, and transit systems that will enhance the available data on publicly owned capital stock.

Other infrastructure data reflect qualitative evaluations of the pavement and associated structures. The condition of highways, bridges, and airport runways has mostly improved in recent years. The percentage of rural Interstate mileage in poor or mediocre condition declined from 35 percent in 1993 to 11 percent in 2003. However, while poor or mediocre urban Interstate mileage decreased from 42 to 27 percent during this same period, urban minor arterial and collector conditions worsened. In contrast, of the nearly 600,000 roadway bridges existing in 2003, 14 percent were deemed structurally deficient and 14 percent functionally obsolete. Ten years earlier, about 33 percent of bridges were either structurally deficient or functionally obsolete. At the nation's commercial service airports, pavement in poor condition remained at 2 percent of runways from 1997 to 2004. For the larger group of several thousand National Plan of Integrated Airport Systems airports, poor conditions existed on 4 percent of runways in 2004, down from 5 percent in 1997.

The age of various transportation fleets is another measure of condition, although not a very precise one. The equipment in air, rail, highway, water, and transit transportation fleets varies widely in terms of scheduled maintenance, reliability, and expected life span. Additional information, such as fleet maintenance standards, actual hours of vehicle use, and durability, would provide a more thorough means for analyzing the condition of a vehicle fleet and comparing fleets across modes.

The median age of the automobile fleet in the United States has increased 19 percent since 1994, from 7.5 years to 8.9 years in 2004. The median age of the truck fleet,4 by contrast, began to increase in the early 1990s but has been declining since 1997 as new purchases of light trucks (including SUVs, pickups, and minivans) have increased substantially.

The age of transit vehicles varies by transit and vehicle type. For instance, from 1993 to 2003, ferryboat fleets aged from an average of 24.7 years to 27.1 years. The average age of full-size transit buses decreased from 8.5 years to 7.3 years during the same period. Similarly, the age of vessels varies by type. While over 30 percent of the overall U.S.-flag vessel fleet was 25 years old or more in 2003, 60 percent of towboats and 48 percent of tank barges were 25 years old or older in 2003. The average age of Amtrak locomotives was 14 years in fiscal year 2001, up 7 percent since fiscal year 1991. The average age of Amtrak railcars declined by 2.5 years during the same period. Finally, the average age of all U.S. commercial aircraft was 12 years in 2002, up from 11 years in 1992.

3. Accidents

Crashes involving motor vehicles and other transportation accidents in the United States result in tens of thousands of fatalities and millions of injuries each year. The number of fatalities and injuries per year represents a common means for evaluating the safety of each transportation mode. Presenting data in the form of the number of fatalities or injuries per 100,000 residents or by pmt or vmt can enable useful comparisons across time and modes. However, care must be taken in doing so, because definitions of fatalities and injuries vary by mode and estimates of vmt and, especially, pmt are inexact.

There were more than 44,000 fatalities related to transportation in 2003, almost 16 fatalities per 100,000 U.S. residents. This is the same rate as in 1993, when there were just over 42,000 deaths. About 94 percent of all transportation fatalities in 2003 were highway-related.

An estimated 2.9 million people suffered some kind of injury involving passenger and freight transportation in 2003. Most of these injuries, about 99 percent, resulted from highway crashes. However, injuries per pmt for most highway vehicle types declined between 1993 and 2003. One exception was the rate for light-truck occupants, which rose 7 percent, from 48 per 100 million pmt in 1993 to 51 per 100 million pmt in 2003.

A RITA/BTS analysis of motor vehicle-related injury data for 20035 shows that there were sharp peaks in injuries associated with youth. For motor vehicle occupants and motorcyclists, the peak spanned ages 15 to 24 years. Young males exhibited a substantially greater peak in serious injuries than did young females (figure 3). In addition, the percentage of injuries classified as serious was greater for motorcyclists (20 percent of all motorcyclist injuries were serious), pedestrians (18 percent), and pedalcyclists (13 percent) than it was for motor vehicle occupants (7 percent).

4. Variables Influencing Traveling Behavior

Travel patterns across the nation are the result of a combination of decisions by individuals and businesses. Travel behavior both shapes and is shaped by available transportation options. Hence, understanding the variables that influence travel behavior is important in evaluating transportation needs and making appropriate decisions about changes in the system.

Results from the 2001 National Household Travel Survey (NHTS), sponsored by BTS and the Federal Highway Administration, show that daily travel in the United States averages about 14,500 miles per person per year. On a daily basis, each person traveled an average of 40 miles, almost 90 percent of it in a personal vehicle. The largest percentage of daily trips (28 percent) was to work. The majority of work trips take place between 7 a.m. and 9 a.m. and between 3 p.m. and 6 p.m.

On average, each person made 9 roundtrip long-distance trips of at least 50 miles per year. Nearly 90 percent of long-distance trips were in personal vehicles; most of the other trips were by airplane. Females and males make a similar number of long-distance trips for pleasure and personal business, but males take 84 percent of long-distance commuting trips and 77 percent of long-distance business trips.

Proximity to transportation options can also affect the modal choices that people make. For instance, in the heavily urban northeast region, 17 percent of households in 2003 did not have a passenger vehicle. A geospatial analysis conducted by RITA/BTS in April 2005 concluded that 93 percent of rural residents in the United States live within a 25-mile radius of an intercity rail station, an intercity bus terminal, or a nonhub or small airport or within a 75-mile radius of a large or medium hub airport.

5. Travel Times

How long it takes people and goods to get from their starting point to their final destination is a key measure of transportation system performance. Current measures of travel time trends tend to focus on delay, congestion, and whether or not scheduled trips arrive on time. While delay and congestion measures are important, they are by no means the only consideration in evaluating these trends.

For those using personal vehicles, highway travel times increased between 1993 and 2003 in all but 2 of the 85 urban areas (98 percent) studied by the Texas Transportation Institute. It took 37 percent longer, on average, in 2003 to make a peak period trip in these urban areas compared with the time it would take if traffic were flowing freely.

The U.S. Department of Homeland Security collects data on the average wait time for over 100 land ports at the U.S.-Canada and U.S.-Mexico borders. The average wait time in 2004 for passenger vehicles crossing the border between the United States and Canada was 6 minutes and 15 minutes for those between the United States and Mexico (figure 4). The average wait time in 2004 for commercial vehicles entering the United States from Canada was 8.5 minutes and 7.3 minutes for those entering from Mexico .

Nearly 78 percent of domestic air flights arrived on time in 2004, compared with 79 percent in 1995. On average, 26 percent of delays in 2004 occurred because of circumstances within an airline's control, such as maintenance or crew problems, while 30 percent happened because a previous flight arrived late. Security delays caused less than 1 percent of delays, on average, and extreme weather 5 percent.

New research at RITA/BTS on an Air Travel Time Index aims to improve the measurement of air travel time and reliability. In preliminary results, the index rose by 4 percent per year between 1990 and 2000 and then fell by 3 percent per year between 2000 and 2004, indicating that the actual travel time for a typical flight became more uncertain and took longer, on average, between 1990 and 2000 and then improved starting in 2001.

Seventy-one percent of Amtrak trains arrived at their final destination on time in 2004, below the system's performance peak of 76 percent in 2002. Short-distance trains-those with runs of less than 400 miles-consistently registered better on-time performance than long-distance trains-those of 400 miles or more from 1994 to 2000 and from 2001 to 2004.6

6. Availability of Mass Transit and Number of Passengers Served

Transit service can be measured in a variety of ways, including passenger-miles of travel and linked and unlinked trips.7 There were 45.6 billion transit pmt in 2003 compared with 36.2 billion pmt in 1993, an increase of 26 percent. As they have historically, buses had the largest pmt share in 2003, generating 19.1 billion pmt or 42 percent of all transit pmt.

Measured in unlinked trips, transit ridership has grown 19 percent since 1993 to 8.9 billion unlinked trips in 2003. Bus ridership comprised the majority of unlinked trips (5.1 billion) in 2003. However, rail transit ridership, with 3.4 billion trips in 2003, posted stronger growth (34 percent) between 1993 and 2003.

Transit use continues to be concentrated in specific markets, such as communities where households do not tend to own cars, in certain large cities, and among lower income households. Approximately 78 percent of all unlinked transit passenger trips (6.9 billion trips in 2003) were within the service area of only 30 transit authorities. New York City alone accounted for 30 percent of all transit trips in 2003.

As of 2003, 55 percent of transit rail stations had complied with the American with Disabilities Act (ADA) accessibility requirements (figure 5). This represented a 178 percent increase from 1993. Ninety-five percent of transit buses, also subject to ADA requirements, were equipped with lifts or ramps by 2003.

7. Travel Costs of Intracity Commuting and Intercity Trips8

On average, U.S. households spent $7,681 (in chained 2000 dollars) on transportation (including vehicle purchases) in 2003 compared with $6,025 in 1993, an increase of 27 percent. Costs related to motor vehicles rose 49 percent between 1993 and 2003, while other transportation expenditures decreased 1 percent. Transportation costs were 20 percent of all household expenditures in 2003; only housing cost more (31 percent).

Driving an automobile 15,000 miles per year cost 53 per mile in 2003, or 20 percent more than it did in 1993, when total costs were 44 (in chained 2000 dollars). For those using transit, the average fare ranged from 17 to 19 per passenger-mile (in chained 2000 dollars) between 1993 and 2003. Increases in fares per passenger-mile for some types of transit service were offset by lower fares per passenger-mile for other types.

On average, intercity trips via Amtrak cost 23 per revenue passenger-mile in 2003, up 46 percent from 16 per revenue passenger-mile in 1993 (in chained 2000 dollars). Meanwhile, average intercity Class I bus fares rose 23 percent, from $23 to $28, between 1992 and 2002 (in chained 2000 dollars).

The RITA/BTS Air Travel Price Index (ATPI) comprises three indexes: U.S. origin flights, foreign origin flights, and combined U.S and foreign origin flights. The ATPI " U.S. origin only" index increased 2.2 percent between the first quarter of 1995 and the fourth quarter of 2004. During the same period, the ATPI "Foreign origin only" index decreased 9.8 percent.

8. Productivity in the Transportation Sector

Two differing indicators of economic productivity exist: multifactor and labor productivity. Labor productivity relates output to labor input, while multifactor productivity relates changes in output to changes in a complete set of inputs, including capital, labor, energy, materials, and services. Multifactor productivity is, thus, a more comprehensive indicator. However, air and rail are the only components of the transportation sector for which multifactor productivity estimates are currently available (from the Bureau of Labor Statistics-BLS); BTS has been developing them for other modes using BLS methodologies.

Labor productivity in the for-hire transportation services and petroleum pipeline industries increased 18 percent between 1992 and 2002, a slower rate than the entire business sector, which rose 24 percent. Among transportation modes, rail increased the most, by 60 percent from 1992 to 2002. Despite a decline of 7 percent between 2000 and 2001, air transportation labor productivity grew 27 percent over the entire period (figure 6).

Multifactor productivity of all business sectors combined increased 10 percent between 1991 and 2001, while multifactor productivity in air transportation increased 16 percent. Data are not available for the same period for rail transportation, but between 1991 and 1999, multifactor productivity in this industry increased by 26 percent (an annual rate of 3 percent).

9. Transportation and Economic Growth

Transportation comprises a sizable segment of the U.S. economy. Total transportation-related final demand rose by 33 percent between 1993 and 2003 (in chained 2000 dollars), from $833.8 billion to $1,112.8 billion. This measure-the value of transportation-related goods and services sold to the final users-is a component of the Gross Domestic Product (GDP) and a broad measure of the importance of transportation to the economy. In 2003, the share of transportation-related final demand in the GDP was 10.7 percent compared with 11.1 percent in 1993.

The contribution of for-hire transportation industries to the U.S. economy, as measured by their value added (or net output), increased (in chained 2000 dollars) from $217.2 billion in 1993 to $314.3 billion in 2003. In the same time period, this segment's share in the GDP fluctuated slightly, remaining at around 3 percent.

The Transportation Services Index (TSI) is a RITA/BTS experimental, seasonally adjusted index of monthly changes in the output of services of the for-hire transportation industries, including railroad, air, truck, inland waterways, pipeline, and local transit (figure 7). The TSI rose to 112.6 in May 2005.9 The separate freight TSI rose to 113.5, while the passenger TSI was at 111.2 in May 2005.

10. Government Transportation Finance

Governments collect revenues and spend money on transportation-related infrastructure and equipment. Federal, state, and local government transportation revenues targeted to finance transportation programs increased 25 percent from $97.4 billion in 1991 (in chained 2000 dollars) to $122.1 billion in 2001.

Spending on building, maintaining, operating, and administering the nation's transportation system by all levels of government totaled $176.2 billion in 2001 (in chained 2000 dollars). Among all modes of transportation, highways receive the largest share of government transportation expenditures. In 2001, government spending on highways amounted to $107.7 billion and accounted for 61 percent of total government transportation expenditures.

Gross government transportation investment,10 including infrastructure and vehicles, is a measure of public transportation capital expansion. Gross investment has risen steadily over the last decade from $62.2 billion in 1991 to $88.8 billion in 2001 (in chained 2000 dollars). Infrastructure accounted for 93 percent of government transportation investment between 1991 and 2001; over 73 percent of infrastructure investment was allocated to highways. Net federal subsidies for passenger transportation have increased from $4,651 million in 1992 to $8,195 million in 2002 (in chained 2000 dollars).

11. Transportation-Related Variables That Influence Global Competitiveness

Transportation contributes to economic activity and to a nation's global competitiveness as a service, an industry, and an infrastructure. It affects the price competitiveness of domestic goods and services because final market prices incorporate transportation costs.

U.S. prices for transportation goods and services in 2001 were relatively lower than prices in 9 out of 24 Organization for Economic Cooperation and Development countries. However, the nation's top two overall merchandise trade partners, Canada and Mexico , had lower relative prices in 2001 than the United States .

The United States traded $329.9 billion worth (in current dollars)11 of transportation-related goods (e.g., cars, trains, boats, and airplanes and their related parts) in 2004 with its partners. As is the case with its overall international trade, the United States had a merchandise trade deficit in transportation-related goods (with an excess of imports over exports) totaling $92.4 billion in 2004. This trade deficit has grown over the years, largely reflecting far greater imports than exports in the automotive sector.

U.S. trade in transportation services in 2004 totaled $133.5 billion (in current dollars) (figure 8). The United States had a surplus in transportation services from 1994 through 1997. The trade surplus was highest in 1996, at $3.3 billion. By 2004, however, 58 percent of trade was imports (payments to foreign countries), resulting in a trade deficit of $21.5 billion-the largest trade deficit for transportation services since 1998.

12. Frequency of Vehicle and Transportation Facility Repairs and Other Interruptions of Transportation Service

Repairs to vehicles, vessels, aircraft, and other transportation equipment as well as roads, bridges, and other infrastructure can impact the schedules of people and movement of goods. Data on repair frequencies can help planners reduce the disruptions they may cause. Unfortunately, data are not readily available to properly characterize the frequency of repairs for vehicles and infrastructure of most modes. There are a number of reasons for this lack of data.

In some cases where repair data are available, establishing a link to service interruptions can be problematic. In other cases, maintenance cost data are available (e.g., airlines and highways), but, again, the connection between costs and frequency and, thus, interruptions of service are not clear. Annual data are available on U.S. domestic vessel fleet capacity, but capacity is linked to market and other factors as well as repair downtime.

Most of the vehicle repair data for the trucks and buses operated by the nation's more than 677,000 motor carriers are not public information. A surrogate measure is data on highway truck inspections. Over 2.1 million roadside truck inspections were completed in 2004, up 9 percent since 1994. The percentage of inspected trucks taken out of service was approximately 24 percent in 1994 and 2004.

Class I railroad companies maintained 169,069 miles of track in 2003, down from 186,288 miles of track in 1993. In 2003, rail companies replaced 632,600 tons of rail (23 percent fewer than in 1993) and 13.2 million crossties (3 percent more than in 1993). Railroads also periodically replace or rebuild locomotives and freight cars. On average, new and rebuilt locomotives made up 4 percent of Class I railroad fleets between 1993 and 2003.

Transit service12 interruptions for all types of transit decreased an average of 3.2 percent per year between 1995 and 2000 and 4.0 percent between 2001 and 2003.13

Natural disasters, accidents, labor disputes, terrorism, security breaches, and other incidents can result in major disruptions to the transportation system. The terrorist attacks of September 11, 2001, and the economic downturn at the time caused decreases in air passenger travel on both domestic and international flights. International travel to and from the United States did not fully recover until 2004 (figure 9). During September 2004, a month of unusually strong hurricane activity in Florida, airlines canceled 124 of every 1,000 flights in and out of the state, compared with only 4 flights per 1,000 in September 2003.

13. Vehicle Weights

Vehicle traffic affects the condition and longevity of infrastructure. Traffic on a given highway segment can be measured by average weights and numbers of vehicles. A way to assess the resultant highway pavement stress is by estimating vehicle loadings14 on the nation's highways. Aircraft landing weights can affect airport pavement, as can the weight of rail equipment on rail tracks. For maritime infrastructure, especially ports, vessel size-often expressed in deadweight tons (dwt), which is a measure of cargo capacity rather than weight-can be of concern. As larger waterborne vessels are added to the worldwide merchant marine fleet, U.S. ports may have to expand to accommodate larger ships or decide to specialize in handling cargoes that are not affected by changes in vessel size.

The number of trucks in the U.S. truck fleet grew 41 percent between 1992 and 2002. In the heavy category (over 26,000 pounds), the number of trucks decreased by 16 percent during the period. While the number of medium trucks (between 6,001 and 19,500 pounds) increased 14 percent between 1992 and 1997, their growth surged 223 percent between 1997 and 2002 (figure 10). Trucks in the medium truck category include heavier pickups and heavier SUVs that have been increasingly sold in recent years. Light trucks, which include SUVs, minivans, vans, and pickup trucks weighing less than 6,000 pounds, represented 74 percent of the truck fleet in 2002, having increased by 24 percent between 1992 and 2002.

Large combination trucks15 made up only 5 percent of traffic volume on urban Interstate highways in 2003, but accounted for 76 percent of the loadings on these highways. In rural areas, they represented 14 percent of traffic and 83 percent of Interstate loadings in 2003. Between 1993 and 2003, large combination truck traffic volume declined from 18 to 14 percent on rural roads, and from 6 to 5 percent on urban Interstate highways.

The average capacity of gas carriers, such as liquid natural gas and liquid petroleum gas vessels, calling at U.S. ports increased 26 percent to 37,818 dwt per call between 1998 and 2003.16 Meanwhile, the average capacity of all types of vessels calling at U.S. ports grew 9 percent, to 49,557 dwt per call in 2003.

The average weight of each freight railcar remained fairly constant-ranging from 62 to 67 tons per carload-between 1993 and 2003. However, this relatively steady average weight of a loaded railcar masks countervailing trends among selected freight commodities. For instance, the average weight of a carload of coal was 111 tons in 2003, up from 101 tons in 1993. Meanwhile, miscellaneous mixed shipment carloads were 13 percent lighter in 2003 than they were in 1993.

14. Transportation Energy

The transportation sector used 17 percent more energy in 2004 (27.5 quadrillion British thermal units-Btu) than it did in 1994 (23.5 quadrillion Btu). Still, transportation energy use grew more slowly than GDP during the period, indicating that the U.S. economy is gradually becoming less energy intensive. Passenger travel (pmt per Btu) was 4.7 percent more energy efficient in 2002 than in 1992, while freight energy efficiency (ton-miles per Btu) declined 2.2 percent.

Decreased energy intensity also makes consumers less vulnerable to changes in energy prices. Transportation fuel prices experienced short-term fluctuations (in chained 2000 dollars) between 1994 and 2004. However, per capita vmt for all modes of transportation increased almost every year. For instance, between 1994 and 2003, per capita highway vmt rose 11 percent, while that of large air carriers grew 26 percent (figure 11).

15. Collateral Damage to the Human and Natural Environment

As people travel and freight is transported, damage can occur to the human and natural environment. Transportation also impacts the environment when transportation equipment and fuels are produced and infrastructure is built, during repair and maintenance of equipment and infrastructure, and when equipment and infrastructure are no longer usable and are discarded and dismantled. The extent of damage throughout these life cycles of transportation fuel, equipment, and infrastructure can vary by mode. In all cases, actual impacts on the human and natural environment are dependent on ambient levels or concentrations of pollutants and rates of exposure.

Transportation vehicles and vessels in 2002 emitted 58 percent of the nation's pollution from carbon monoxide (CO), 45 percent of nitrogen oxides (NOX), 36 percent of volatile organic compounds (VOC), 4 percent of particulates, 8 percent of ammonia, and 5 percent of sulfur dioxide. Highway vehicles emitted almost all of transportation's share of CO emissions in 2002, 78 percent of the NOX, and 77 percent of all VOC.

Transportation emissions of greenhouse gases (GHGs) grew 19 percent between 1993 and 2003. Nearly all (95 percent) of CO2 emissions-the predominant GHG-are generated by the combustion of fossil fuels. Transportation CO2 emissions grew 19 percent between 1993 and 2003.

Transportation-related sources typically account for most oil spills into U.S. waters reported each year to the U.S. Coast Guard. For instance, transportation's share of the reported total volume of oil spilled between 1991 and 2001 varied from a high of 97 percent (in 1996) to a low of 77 percent (in 1992). The volume of each spill varies significantly from incident to incident. One catastrophic incident can, however, spill millions of gallons into the environment.

Transportation can also affect human health and the environment when hazardous materials accidents occur. Transportation firms reported more than 14,740 hazardous materials incidents in 200417 (figure 12). These incidents resulted in 13 deaths and 289 injuries, compared with annual averages of 22 deaths and 345 injuries between 1994 and 2004.

Summary of The State Of Transportation Statistics (Chapter 3)

The U.S. Congress directs RITA/BTS to collect, compile, analyze, and publish a comprehensive set of transportation statistics, including information on a list of topics specified in legislation. RITA/BTS is to include information on these topics in this annual report.

In 2005, Congress, in the Safe, Accountable, Flexible, Efficient Transportation Equity Act-A Legacy for Users (SAFETEA-LU), expanded the topic list, adding security and putting additional emphasis on goods movement, intermodalism, connectivity, infrastructure, and vehicle coverage (table 1-1). Chapter 3 discusses data needs for these topics in SAFETEA-LU under the six headings below.

Movement of People, Goods, and Vehicles on the Nation's Transportation System

Traffic flows. Data on the flow of people, goods, and vehicles on the transportation system is useful in evaluating current system capabilities, planning future infrastructure needs, and understanding other transportation topics such as energy use and safety risks.

A complete picture of freight and passenger flows is not available from any single source. National multimodal surveys, such as the CFS for goods and the NHTS for passenger travel, have provided widely used national benchmark data. These surveys are conducted infrequently (with CFS data last collected in 2002 and NHTS data in 2001/2002) and do not encompass all movements or provide detailed geography. Mode-specific data from a variety of sources can be used to fill some of the gaps, at least in the case of freight. Hence, RITA/BTS and the Federal Highway Administration (FHWA) are developing an extended dataset to provide a more complete national picture of freight flows than is currently available from the CFS survey alone [3].

The 2001/2002 NHTS covered local and long-distance travel and all modes of transportation. The sample size was insufficient for identifying trip origins and destinations or providing detailed geography (although some states and localities paid to get more detail for their areas). Mode-specific data from operators and other sources can be useful in evaluating flow trends, but data for some types of activities such as trips by bicycle or on foot are sparse.

Data on the movement of people, vehicles, and goods across U.S. borders are important for economic, security, and flow analysis. Using data collected from Customs and Border Protection of the Department of Homeland Security, RITA/BTS compiles and disseminates data on the number of people, vehicles, trains, and containers crossing between the United States and both Canada and Mexico (figure 13 and figure 14).

Availability and use of for-hire passenger modes. SAFETEA-LU expanded RITA/BTS's mandate to provide information on availability and use of mass transit to all for-hire passenger modes (e.g., intercity train, intercity scheduled and charter bus, local taxis, commercial air, air taxi, and air charter). Some of these data are available from Department of Transportation modal administrations and a number of public and private sources such as Amtrak. RITA/BTS collects air passenger data.

National statistics to track trends in routes and schedules across for-hire modes are spotty. RITA/BTS evaluations of scheduled air, train, and intercity bus service for over 200 city pairs, and separate studies of the proximity of rural Americans to for-hire intercity transportation services, have contributed data for a fuller understanding. A possible next step in this analysis is the evaluation of intermodal connectivity of the passenger transportation network, which could help provide a more complete picture of modal access.

System Status

Data pertinent to transportation system status include, among other things, physical extent, connectivity, and condition of transportation infrastructure; physical characteristics of the vehicles and other conveyances that use the infrastructure; capital investment in the system; and infrastructure availability for use as reflected in travel times, congestion, and service interruptions.

System extent, connectivity, and condition. An enormous amount of information exists about the extent and location of transportation facilities, the number and nature of connections within and between modes, and the physical condition of system components. Such data can be aggregated into summary tabulations, such as the RITA/BTS publication National Transportation Statistics, and a companion volume of state-level data [2]. It is often very useful to portray the geographic context of transportation data, such as through the RITA/BTS National Transportation Atlas Database, which displays transportation data, including facilities and networks, at a national, regional, state, and local level.

Travel times and congestion. RITA/BTS publishes monthly summaries of on-time performance for large U.S. air carriers and data on causes of delays. Additionally, an Air Travel Time Index measures the change in the difference between scheduled travel times and actual travel times for nonstop flights in the United States (figure 15).

Not all travel time data is made public by private carriers, making trend analysis difficult. If data can be aggregated from a suitable number of firms while maintaining privacy rights, measures of travel time across an industry can be conducted. RITA/BTS has developed such a measure for overall line-haul speeds for the rail freight industry, allowing for historical comparisons.

The best way to measure congestion remains a subject of debate. Research conducted by FHWA summarized the data challenges [1]. In essence, additional work must be done to collect sufficient data by a standardized approach so that congestion can be compared in a particular region or across various regions.

Transportation capital stock and financing. Capital stock takes into consideration the quantity and condition of infrastructure and vehicles. The Bureau of Economic Analysis in the U.S. Department of Commerce compiles data on private sector transportation capital stock and public sector highways and streets (figure 16). RITA/BTS has been developing measures for other publicly owned transportation capital stock, including airports, waterways, and transit systems.

Economic and Other Variables Affecting Travel and Goods Movement

Variables influencing travel behavior. Access to transportation, travel costs, employment status and location, income, location of housing and services, family status, age, and disabilities are a few of the demographic, economic, and other variables influencing travel behavior. Information on passenger characteristics is available from the NHTS. Goods movement is influenced by the economy and population and its geographic distribution, including the location of goods producers, suppliers and customers in relation to each other, and proximity of transportation facilities and services.

Performance of the domestic economy and U.S. competitiveness. There is extensive data available that relate to the performance of the domestic economy and U.S. global competitiveness. Among the variables that may be considered are relative prices of goods and services, relative productivity, transportation infrastructure, international trade, and employment. Many sources of these data, including government and private transportation investment, capital stock, and productivity, are discussed under other SAFETEA-LU topics.

Transportation sector productivity. Productivity data is primarily the work of the Bureau of Labor Statistics. In general, productivity measures describe the relationship between the quantity of output produced and the inputs (labor and capital) used. BLS currently provides labor productivity data for air transportation, line-haul railroads, and general freight trucking (long-distance) and multifactor productivity data for air transportation. RITA/BTS has been working on multifactor productivity data for other modes.

Cost of passenger travel and goods movement. The RITA/BTS Air Travel Price Index measures the change over time in the actual prices paid by air travelers. The index can be used to compare airfares in the most recent quarter available with any quarter since the 1995 base year. The index reflects fares paid by travelers, not published fares, using survey data from a 10 percent sample of all U.S. carrier airline tickets, excluding charter air travel. Similar indexes are not available for other modes.

Safety and Security

SAFETEA-LU expanded the topic of accidents in prior legislation to the broader topic of the safety and security of passengers, vehicles, and transportation systems. This poses some data availability problems as much of the security data that are collected are no longer publicly available or available in a more limited form.

Differences among vehicles have implications for safety data. Changes in consumer preferences for vehicles, such as the rapid increase in sales of sport utility vehicles and other light trucks over the last 15 years, has made crashes more common between these larger vehicles and smaller passenger cars, and also has raised issues about the vehicles themselves (figure 17). Data on crashes involving more than one mode of transportation, such as passenger cars or bicycles with trains at grade crossings, remains an important topic. Safety incidents involving freight and passenger modes, which often share the same facility or road, present data challenges.

Unintended Consequences

The U.S. Environmental Protection Agency (EPA) and the Department of Energy's Energy Information Agency (EIA) are the primary agencies collecting data used to evaluate transportation's effect on the natural environment. EPA collects data to measure national air pollutant emissions from transportation vehicles, disposed amounts of some types of transportation equipment, and air quality across the nation. EIA is responsible for collecting data on fossil fuel use, an important component of transportation energy use. The Coast Guard previously reported oil spill data from all sources. However, its current emphasis on security has changed data-collection priorities such that current oil spill data focuses on marine vessels and structures, with little data on other transportation sources.

A Concluding Note

RITA/BTS has been reporting on important transportation data needs in this report annually, as well as in other reports over the years. In addition to expanding the scope of data issues in 2005, the U.S. Congress has mandated that the Secretary of the U.S. Department of Transportation (DOT) enter into an agreement with the National Research Council to assess national transportation information needs. The study, due for completion in the fall 2007, is to be followed by a DOT report to Congress on ways to fill data gaps. It is evident that the need remains for relevant, timely, high-quality transportation information for decisionmaking.

References

1. U.S. Department of Transportation, Federal Highway Administration. 2004. Traffic Congestion and Reliability: Linking Solutions to Problems. Available at http://www.ops.fhwa.dot.gov/congestion_report/, as of September 2005.

2. U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics. 2004. State Transportation Statistics. Washington, DC. Also available at http://www.bts.gov/.

3. ______. 2005. Freight in America . Washington, DC.

1 See 49 U.S. Code 111(c)(1), subsections A through L. Topics are listed here in the order in which they appear in this report; the letter in parentheses is the subsection in the legislation. Topics 9, 10, and 14 are not in the legislation but were added by RITA/BTS.

2 All dollar amounts are expressed in chained 2000 dollars, unless otherwise specified, to eliminate the effects of inflation over time. See the Glossary for definitions of constant, chained, and current dollars.

3 Preliminary data are used here because, while final 2002 CFS data were available at the time this report was prepared, supplemental data were still forthcoming.

4 This includes all truck categories: light, heavy, and heavy-heavy.

5 This analysis was based on data from the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System. Due to methodological differences, these data are not necessarily consistent with other injury data in this report that come from the U.S. Department of Transportation, National Highway Traffic Safety Administration's National Automotive Sampling System General Estimates System.

6 Amtrak revised its methodology for collecting and calculating on-time performance data in 2001.

7 For a discussion of linked vs. unlinked trips, see section 6 in chapter 2.

8 To eliminate the effects of inflation over time, all dollar amounts in this section and throughout most of the report are expressed in chained 2000 dollars, unless otherwise specified.

9 The TSI is a chained-type index where the year 2000 = 100.

10 See section 10 in chapter 2 for detailed descriptions of transportation investments.

11 All dollar amounts in this section on global competitiveness are in current dollars. While it is important to compare trends in economic activity using constant or chained dollars to eliminate the effects of price inflation, it is not possible to do so in this instance (see notes on chapter 2 figures and corresponding tables in appendix B).

12 See detailed definitions of the type of transit equipment included in section 12 in chapter 2.

13 Data from 1995-2000 and 2001-2003 were collected using different definitions of what constitutes an interruption of service and are not comparable.

14 Vehicle loadings are based on equivalent single-axle loads.

15 Large combination trucks weigh more than 12 tons and have 5 or more axles.

16 1998 is the first year for which data are available.

17 See section 15 in chapter 2 for a definition of a reported incident.