Chapter 3
State of Transportation Statistics

Data collection, compilations, and analyses by the Bureau of Transportation Statistics (BTS) of the U.S. Department of Transportation (DOT) focus on five core transportation data areas: freight, passenger travel, air transportation, economic, and geospatial. The previous edition of Transportation Statistics Annual Report (TSAR)¹ presented an overview of why these data are important to the transportation community, reviewed the existing data, and presented possible options for filling crucial data gaps. This edition of TSAR expands on that presentation by providing information on how BTS programs and projects are filling data gaps and improving the state of transportation statistics in other ways.

Improving the Knowledge Base for Freight Planning

Changes in freight transportation reflect the dynamic nature of national and global economies, growth in domestic and international trade, and continuing improvements and innovations in technology. Alterations in the mix of manufactured products, shifts in global production and trade patterns, and growing domestic demands from industry and consumers all affect freight transportation and related data needs. Meeting these needs can be challenging for data providers. The Transportation Research Board (TRB) in 2003 reaffirmed the importance of freight data for guiding decisions on infrastructure investments and policymaking affecting both the public and private sector [2]. TRB found several shortcomings in the current freight data system and recommended that DOT, with the assistance of BTS, develop a national freight data framework.

The Commodity Flow Survey (CFS), conducted by the U.S. Census Bureau for BTS, is the most extensive, long-running national survey of domestic freight activity. After a 15-year hiatus, CFS data collections began again in 1993, after BTS was created, and were repeated in 1997 and 2002. BTS and the Census Bureau released preliminary data from the 2002 CFS in December 2003; data were made available to users on the BTS website. Although the CFS is the most comprehensive multimodal source of national freight data, it does not cover all freight shipping industries and excludes most imports. For the near future, BTS is considering a number of ways to enhance freight data, such as conducting small surveys of sectors not covered by the CFS and seeking ways to obtain data directly from carriers. To provide more detail, BTS is also considering increasing the sample size of the CFS. In the meantime, BTS has augmented CFS national totals by adding supplemental freight data from other sources. BTS published Freight Shipments in America: Preliminary Highlights from the 2002 Commodity Flow Survey in April 2004 with combined CFS and supplemental data [7]. (See "Commercial Freight Activity" in chapter 2, section 2.)

The changing needs of policymakers, the freight industry, transportation planners, and others have converged on the necessity of finding new approaches for collecting, analyzing, and disseminating freight transportation data. Accordingly, BTS is planning a National Freight Data Program to expand coverage and increase collection frequency of freight flow data and integrate information collected from a variety of sources, such as the CFS, other targeted surveys, and intelligent transportation system data; provide new data access tools and models; and release periodic reports and special products.

Tracking Freight and International Trade

International freight flows data are important not only for tracking the growth of imports and exports but also for assessing the domestic transportation requirements and impacts of trade. In January 2004, BTS released a preliminary report, "International Trade Traffic Study." This report, on domestic highway movements associated with international trade, was prepared in response to section 5115 of the Transportation Equity Act for the 21st Century. Using CFS and other freight data, BTS found that imported goods and goods headed for export carried on domestic highways in 1997 totaled nearly 227 billion ton-miles. After a committee of the National Academy of Sciences concurred with the report's major findings, BTS transmitted the final report to Congress in May 2004.

Canada and Mexico are not only the United States' trading partners under the North American Free Trade Agreement but also its two largest trading partners worldwide. Two BTS data programs provide detailed information on this trade and vehicle passage across U.S. borders. Border Crossing Data counts incoming vehicles, containers, passengers, and pedestrians at land gateways on the U.S.-Canadian and U.S.-Mexican borders. BTS obtains the original data from the Bureau of Customs and Border Protection (CBP) of the Department of Homeland Security (DHS). The data have been disseminated since 1994; annual data are available on the BTS website and monthly data can be requested from BTS by telephone or email.

Trade corridor studies, transportation infrastructure planning, marketing, and logistics analysis require mode-specific trade data. The Transborder Freight Data program has been making such data available on a monthly basis since April 1993 for surface modes, such as rail, truck, and pipeline. Included are merchandise trade data by commodity type and by mode with geographic detail for U.S. exports to and imports from Canada and Mexico. BTS is expanding the program's coverage in 2004 to include trade with Canada and Mexico involving air and water modes. BTS derives the transborder freight data from official U.S. international merchandise import and export trade data collected by CBP and provided to BTS by the U.S. Census Bureau.

In the longer term, with expected continued growth in international trade, timely and complete data on modes and commodities associated with this trade will be critical. Several federal agencies are working to put in place the International Trade Data System (ITDS) aimed at accelerating the phase-in of electronically filed trade documents, thus allowing much more rapid processing of trade data than is now possible. BTS is working with other DOT operating administrations and the ITDS managers at CBP to ensure that this new data system includes transportation-related data. The development of ITDS is expected to take many years, but initial data on truck manifests is scheduled to be provided to DOT's Federal Motor Carrier Safety Administration in late 2004.

Understanding People's Attitudes, Opinions, and Use of the Transportation System

Knowing how, why, when, and where people in the United States travel is one of the most basic data needs of transportation policymakers, planners, and others. While the federal government has long been collecting these types of data, two BTS surveys have been instrumental in providing comprehensive datasets on a periodic basis for a number of years.

Most recently, data were collected by BTS and the Federal Highway Administration (FHWA) in the 2001 National Household Travel Survey (2001 NHTS). These new data will help us understand how people use the transportation system for local and long-distance travel. In this new survey, specific questions were added to capture biking and walking trips-trips thought to be underrepresented in prior surveys. The definition of long-distance travel was expanded to include one-way trips as short as 50 miles and trips made for the purpose of commuting to work from more distant locations. The survey also introduced the first look at the daily travel characteristics of children under five years of age.

In addition to making 2001 NHTS data available online and on CDs, BTS and FHWA have produced various analyses of the survey data. An overview, NHTS: Highlights of the 2001 National Household Travel Survey, provides background on the survey itself, details the household characteristics captured, and summarizes the results of daily and long-distance travel [9]. In the America on the Go series, BTS focused on specific issues, such as holiday and business travel [3, 4]. (See chapter 2, section 5 for 2001 NHTS data and analyses.)

For three years, BTS conducted the Omnibus Survey on a regular basis to ascertain people's usage of the country's transportation system. Data were also gathered on what people think about the system and to gauge public satisfaction with government programs. Surveys were often conducted with the cooperation of DOT operating administrations. The wealth of data collected by Omnibus Surveys resides on the BTS website, available for use by policymakers and planners at national, state, and local levels. On the website under the title OmniStats, BTS has published analyses of Omnibus data. These short reports cover topics such as airline passengers' views of airport security screening; walking, bicycling, and recreational boating frequencies; commuting trends; and congestion experiences. (See "Survey Data on Congestion Delays" in chapter 2, section 3.)

Supporting State and Local Transportation Planning

Across the nation, metropolitan planning organizations (MPOs) are responsible for ensuring that transportation planning meets the needs of their communities and the people who live in them. National data are only partially useful within this context. A number of efforts to provide more detailed data are underway.

How people get from home to work and back and how these patterns change over time is essential data for transportation planners at the state and local level. With each decennial census, the U.S. Census Bureau collects this "journey-to-work" (JTW) data. Most importantly for local purposes, the data can be aggregated at a transportation analysis zone (TAZ) level.² Since 1960, various government entities and associations have cooperated to pay for and disseminate special tabulations of JTW decennial data. BTS provides statistical quality assurance staffing for a JTW project team. The team released county and state profiles of the Census Transportation Planning Package 2000 (CTPP 2000) in October 2002, containing selected transportation-related data items from the 2000 and 1990 censuses.³ A programming format version of final CTPP 2000 Part I data was released in February 2004 containing tabulations for residence geography. Similar place-of-work data (Part 2) and JTW flow tables (Part 3) were expected in summer 2004.⁴ BTS is responsible for distribution of CTPP data to the general public and responds to technical queries. In addition, BTS plans to develop a geographic information system (GIS) web-based access tool to give users of CTPP 2000 data mapping capability through its TranStats website.

A more robust provision of JTW data may arise from a Longitudinal Employer-Household Dynamics (LEHD)⁵ pilot program, initiated by the U.S. Census Bureau. The aim of this program is to demonstrate the potential for linking existing economic administrative records with survey demographic data. BTS is participating in the pilot by conducting research to develop detailed origin and destination tables. This research effort will combine information about U.S. workers (place of residence, employment, and income) and employers (location, type of business, number of employees, and payroll). Once available, these data will illustrate the travel flow of workers to places of employment. It is anticipated that LEHD data will provide greater geographic specificity than has been available in the past and will lead to the ability to derive enhanced travel demand patterns for use by transportation researchers, planners, and engineers.

While the 2001 National Household Travel Survey (see above) was primarily a national sample, an additional 40,000 households were surveyed in 9 jurisdictions. Four of these were the urban areas of Baltimore, Maryland; Des Moines, Iowa; Lancaster, Pennsylvania; and Oahu, Hawaii. The other five jurisdictions were the states of Hawaii, New York, Texas, and Wisconsin and four counties in Kentucky. The costs of these additional surveys were borne by the individual jurisdictions. The local and state data generated, which include all of the components of the national sample, will not only assist planners in these jurisdictions directly but also provide valuable insights at the national level.

Connecting Transportation to People's Needs

Some transportation modes can be underrepresented in major surveys. Some groups, such as the elderly and disabled, have special needs. Other people may reside in areas not well served by public transportation. BTS has augmented data on these and other special transportation issues with more specific surveys and studies.

With the National Highway Traffic Safety Administration, BTS conducted a separate survey in 2002 to better understand the scope and magnitude of bicycle and pedestrian activity and the public's behavior and attitudes regarding bicycling and walking. According to responses to the National Survey of Pedestrian & Bicyclist Attitudes and Behaviors, approximately 57 million persons aged 16 or older rode a bicycle during the summer of 2002 [11]. During this period, 8 out of 10 of the people in this age group (79 percent) walked, ran, or jogged for 5 minutes or more at least once. The survey data can be useful in a number of ways, such as analyzing the links between walking and bicycling and infrastructure and how perceptions of walkers and nonwalkers differ. (See "Daily Travel by Walking and Bicycling" in chapter 2, section 2.)

With its 2002 National Transportation Availability and Use Survey, BTS sought data on people with and without disabilities to help transportation policymakers and planners create systems that serve everyone equally. Both those with and without disabilities reported similar difficulties in using the transportation system: bus and airline schedules not being kept, inadequate seating on subways and airplanes, and insensitive drivers encountered while walking or biking. However, 12 percent of people with disabilities have difficulty getting the transportation they need, compared with 3 percent of persons without disabilities. About 528,000 disabled people never leave home because of transportation difficulties [5].

The reduction in air services after September 11, 2001, amid an ongoing gradual decrease in rural services by other modes, has raised questions about the mobility of the country's 82 million rural residents. To quantify the availability of air, rail, and intercity bus services for this population group, BTS conducted a Rural Access to Transportation GIS analysis in January 2003. This study plotted each of the nation's intercity bus stations, rail stations, and commercial airports. It defined rural populations residing within a 25-mile radius of bus and rail stations and smaller airports as having reasonable access to these modes of intercity transportation. For medium and large hub airports the study used a wider 75-mile coverage radius. The study's use of GIS techniques enabled BTS to show that nearly 78 million rural residents (94 percent) are within the coverage radius of at least one intercity transportation facility. The study is covered comprehensively, in a report, Scheduled Intercity Transportation: Rural Service Areas in the United States [8]. Both maps depicting the research findings and the report are available on the BTS website. (See "Scheduled Intercity Transportation in Rural America" in chapter 2, section 5.)

Understanding the Transportation Industry

Transportation, a major U.S. industry, is multifaceted. Carriers in the for-hire transportation industry are in the business of transporting people and goods. Other firms, such as many large retailers and grocers, use their own fleets of trucks or other vehicles to transport goods and people. Mode-specific data can be key to understanding transportation industry trends, but most data collected generally apply only to the for-hire component. Detailed modal data arising from business operations were once commonly reported to government regulatory agencies by carriers. With deregulation in the 1970s and 1980s, many of these reporting requirements were eased or eliminated, although some aspects, such as safety reporting, continued to be extensive.

Reporting on financial and operating conditions does continue for some modes. Air carriers report monthly and quarterly data for a number of measures and activities to BTS. These data include Airline Financial and Operating Statistics for both passenger and freight components of the industry and are useful in benchmarking, investment planning, competitive analyses, and for other purposes. BTS prepares quarterly reports on domestic airline financial data such as operating profit/loss margins, unit revenue and costs, and revenue yield by both individual airline and airline groupings. In addition, BTS collects and makes available data on airline on-time performance. In 2003, BTS began reporting data on the causes of flight delays. All of these data and reports are available on the BTS website.

Trucking firms transported 66 percent of freight tonnage nationwide in 2002.⁶ Financial and operating data reported to the government by these firms, however, is far less extensive than that of the air industry, since less than 5 percent of the country's motor carriers report Motor Carrier Financial and Operating Statistics data to BTS. Reporting frequency of Class I and Class II trucking and bus companies varies depending on a firm's category and size.⁷ Policymakers, academics, and the industry itself use these data for benchmarking and competitive and other types of analyses. After verification and quality control, BTS makes the nonconfidential motor carrier data available to the public through its website and TranStats database. BTS has produced annual reports covering data from 1994 through 2001; selected quarterly earnings data reports are available for 1995 through 2001.⁸

Linking Transportation and the Economy

Transportation's contribution to the U.S. economy can be measured in a number of ways, including:

• For-hire transportation industry Gross Domestic Product (GDP)-the value added to GDP by this sector of the economy.
• For-hire GDP plus in-house transportation services GDP-the latter is the value added to GDP by firms that operate their own, internal transportation services.
• Transportation final demand-the value of transportation-related goods and services (not necessarily produced by the transportation industry) sold to consumers and government, such as cars and gasoline, and transportation equipment purchased by industries as investment.
• Transportation-related GDP-the value added by transportation services, as well as the value added by various intermediate inputs to transportation, such as diesel fuel, trucks, and business services.
• Transportation-driven GDP-adds to transportation-related GDP more distant inputs down the production chain, such as the steel and glass that are used to make vehicles.

On a value-added basis, about 3.2 percent of the economy is produced by firms in the for-hire transportation industry, such as trucking, railroads, and waterborne shipping. In-house trucking services contribute another 1 percent or more.⁹ (See "Transportation and Economic Growth," section 13 of chapter 2.)

After a development period of three years, BTS released the Transportation Services Index (TSI) in March 2004. The TSI is a monthly, seasonally adjusted measure of the volume of services performed by the for-hire transportation sector. The index, with a base year of 1996, covers the activities of for-hire freight carriers, for-hire passenger carriers, and a combination of the two since 1990. Still an experimental index, BTS continues to make refinements in data and methodologies while releasing online updates monthly.

The TSI shows the increases or decreases in the output of transportation services from month to month, using ton-mile or passenger-mile data where available monthly, or proxies (e.g., tonnage or passengers) when not. Useful in itself as an indicator of overall freight and passenger industry activity, the movement of the index over time also can be compared with other economic measures to understand the relationship of transportation to long-term changes in the economy. (See "Transportation Services Index" in chapter 2, section 13.)

Work underway at BTS on Transportation Satellite Accounts will determine the full contribution of transportation to the economy. Current Bureau of Economic Analysis (BEA) data on transportation services only cover for-hire transportation. BTS's aim is to fill the gaps in knowledge of in-house transportation services. These services include, for instance, private fleets of trucks used by grocery firms to carry products from their warehouses to their stores. BTS previously published 1992 and 1996 data on in-house trucking and bus transportation.¹⁰ Work underway will produce 1997 data on rail, air, water, and private car transportation and a methodology to enable annual updating capabilities.

A comprehensive set of modal Capital Stock data would enable policymakers and others to, for instance, better estimate the amount of investment needed to accommodate current or future levels of traffic and would improve modal productivity measures. While BEA compiles transportation capital stock data, they pertain mostly to that owned by the private sector. The exception is data on the dollar value of public highways and streets. BTS is developing values for publicly owned airport and airway capital stocks, waterways, and transit systems. Capital stock is a commonly used economic measure of the capacity of the transportation system. It combines the capabilities of modes, components, and owners into a single measure of capacity in dollar value. This measure takes into account both the quantity of each component (through initial investment) and its condition (through depreciation and retirements). (See "Transportation Capital Stock" in chapter 2, section 11.)

Productivity measures are critical to assessing how effectively the nation is enhancing the performance of its transportation system. Labor productivity-a commonly used measure-is based on a single factor, such as output per labor hour. Multifactor Productivity (MFP) provides a more comprehensive view of productivity. One MFP methodology, for instance, employs growth rates of inputs weighted by their income shares. The Bureau of Labor Statistics (BLS) currently produces MFP data for the railroad and air transportation industries. BTS is developing the methodology for and anticipating the production of MFP data for other transportation industries. Trucking MFP data will be the first product of this new dataset. (See "Labor Productivity in Transportation" and "Multifactor Productivity" in chapter 2, section 1.)

Improving the Nation's Price Indexes

While data on the costs of travel by various modes are available, it is not always possible to do relevant comparisons because of the variety of different measurements in use. BTS, in collaboration with BLS, has developed a new method of computing price indexes for air travel that one day might serve as a model for producing price indexes for other modes.

The Air Travel Price Index (ATPI) uses data from the Origin & Destination Survey through which BTS collects information on a 10 percent sample of all airline tickets purchased. BTS developed the ATPI to improve on traditional measurements that are complicated by the variety of discount fares airlines now offer directly and through the internet and by frequent flyer programs. BTS released the still-experimental ATPI data in March 2004. The agency makes available a range of datasets (by airport and category) in figure and table form on its website and allows users to create customized sets by airport. Research on the ATPI has shown that it generates different results than does the Airline Fare Index, a component of the Consumer Price Index (CPI) produced by BLS. While developing a production system, BTS plans to do quarterly updates of its research data. BTS is also working with BLS to improve the accuracy of airfare indexes overall. (See "Air Travel Price Index" in chapter 2, section 6.)

Understanding the Relationship between Transportation and the Environment

As people travel and freight is transported, damage can occur to the human and natural environment. While much data are available on air pollutants emitted from transportation vehicles of all kinds, less is known about other pollutants and about the direct relationship between transportation emissions and public health or the economy.

BTS is assisting the DOT Center for Climate Change and Environmental Forecasting with the GIS component of a research project to better understand the impact of climate change and variability on the U.S. transportation system in the Gulf Coast region. This multiyear research effort, which is being conducted under the auspices of the interagency Climate Change Science Program, aims to assist transportation planners in making decisions that result in a more robust and reliable transportation network.

A BTS-managed project for the DOT Center for Climate Change and Environmental Forecasting will assess the feasibility of developing a measure of the Transportation Greenhouse Gas Intensity of the Economy. Such a measure for the U.S. economy as a whole was introduced by the Bush Administration in February 2002, setting a goal of reducing the greenhouse gas intensity of the economy by 18 percent by 2010. The study of a transportation-related measure is expected to provide data and information on the validity of various measurements, such as those based on different greenhouse gases, vehicles, and fuel types and by mode of transportation. In addition, the study will investigate the validity of an aggregate transportation measure. (See "Greenhouse Gas Emissions" in chapter 2, section 10.)

Demonstrating Accountability to the Public

Under the Government Performance and Results Act (GPRA), each federal agency must develop a performance plan and report annually on its progress. Another component of accountability is making sure that DOT programs are relevant to people who rely on them. As mentioned above, the BTS Omnibus Survey included questions about people's knowledge of and attitudes about DOT programs.

To assist in DOT's implementation of GPRA, BTS provides performance measurement and statistical methodology support to the Office of the Secretary of Transportation and DOT's operating administrations. Specifically, BTS helped DOT develop its verification and validation plan, write data details on the strengths and weaknesses of measures used in performance reports and plans, and build projections and estimates for indirect measures. BTS also develops improved measures and compiles aggregate DOT safety measures. The annual DOT performance plan has twice been rated in the top two of all government agencies. George Mason University's Mercatus Center emphasized DOT's transparency of information in data details in its fiscal year 2002 report [1].

Enhancing the Tools for Data Users

Managing raw data can be time consuming and resource intensive. Improvements in data analysis tools can reduce those costs, as well as increase the quality of the analysis. BTS has produced a number of such tools, especially using GIS technology.

The geographic relationships between freight movements and infrastructure can be displayed graphically by GeoFreight, a new tool produced by BTS, FHWA, and the Office of Intermodalism of DOT. This tool helps freight policymakers and planners identify the flows of domestic and international freight across the country and assess major freight bottlenecks in the transportation system. GeoFreight can display information on freight traffic flows by mode (highway, rail, and water); examine freight activity at key access points (highway-seaport, highway-airport, and highway-rail terminal); analyze origins and destinations of freight movements on highways and rail and maritime networks; and display freight volume data in relation to infrastructure, traffic delays, and trade. The tool employs data from FHWA's Freight Analysis Framework and other sources. GeoFreight is available on a CD; BTS provides technical assistance to users [10]. (See "Geography of Domestic Freight Flows" in chapter 2, section 2.)

Another GIS product produced by BTS, the National Transportation Atlas Database (NTAD),¹¹ is a set of nationwide geographic databases of transportation facilities, transportation networks, and associated infrastructure. Included are spatial information for transportation modal networks and intermodal terminals, as well as the related attribute information for these features. While the data are most useful at the national level, they also have major applications at the regional, state, and local levels. Each database is supported by metadata documentation, as prescribed by the Federal Geographic Data Committee. NTAD 2004 is available from BTS in a two-disk CD set [6]; 2000 through 2003 versions are available on the BTS website.

Improving the Quality of Transportation Data

The quality and utility of transportation data and datasets can be problematic. Data can be irrelevant to some key users, suffer from definitional issues that reduce their usefulness, be collected too infrequently, not be comparable with other relevant data, have omissions, or contain errors. Data quality reviews can uncover these problems and pose solutions. An end result of higher quality data is more accurate information for policymakers and others.

Under the BTS Data Quality Review program, the agency has conducted several in-depth assessments of DOT data systems, providing recommendations and suggestions for data quality improvements to data managers. Data quality assessments have included Airline Traffic and Financial data, Airline On-Time Performance data, the Hazardous Materials Information System, the safety and security module of the National Transit Database, and the Unified Shipper Enforcement Data System. The program has also provided data quality assistance to various DOT administrations, conducted statistical reviews of BTS products, and developed various data quality methods to support BTS work.

Quality can also be enhanced through the use of standards. Legislation enacted in 2000 (the so-called Information Quality Act),¹² required all federal agencies to develop Information Quality Guidelines by October 1, 2002. Using an intra-agency committee process, BTS developed the statistical portion of DOT's Information Dissemination Quality Guidelines. The result was a comprehensive set of guidelines that cover all aspects of the data-collection process from planning through dissemination. In May 2003, the Center for Regulatory Effectiveness, an organization working to ensure that information federal agencies disseminate to the public is of the highest quality, commended DOT on its statistical guidelines, citing their completeness and specificity. DOT's guideline document is available on the department's website.¹³

Opening Up Access to Information: Citizen-Centered Government

Because people use a variety of ways to gain needed information, BTS's data collections, compilations, and analyses are available in print, on its website, and on CDs. In addition, BTS operates an interactive answer line (accessible by telephone or email) to help people determine what specific information would address their needs and where they can get it.

The BTS TranStats website provides downloadable data from over 100 transportation databases as well as links to many transportation datasets stored on other agency websites. Its unique features include a searchable index of the included databases; selective download into formats usable by most databases, spreadsheets, or statistical packages; online data documentation; and interactive analytical and mapping tools. This BTS-designed combination of tools and capabilities greatly simplifies the labor-intensive process of finding, gathering, compiling, and analyzing transportation data.

Many in the transportation community need quick access to compiled data. To serve this need, BTS has produced the National Transportation Statistics (NTS) report since 1993.¹⁴ Compiled from a variety of sources, NTS now provides, in print and online versions, over 190 tables of the most frequently used transportation data. Data tables are grouped into four sections: the transportation system, safety, economy, and energy and the environment. Once an annually updated publication, NTS's online version is now updated as new data become available. Starting with the 2002 issue, BTS publishes a print version every two years. Annually, BTS produces the Pocket Guide to Transportation containing key datasets and figures.

Making Comparisons Easier

Relevance and other measures of progress are often determined by comparing results. The data collections presented in NTS provide one way comparisons can be made, especially among modes of transportation. Other comparisons, across states and internationally, have been facilitated through other BTS efforts.

Federal agencies collect much state transportation data, but its usefulness at the state level is reduced by the disaggregated nature of the various collections. Between 2001 and 2003, BTS produced a series of individual State Transportation Profiles covering all 50 states and the District of Columbia. Each profile provided-through tabular data-a picture of each state's infrastructure, freight movement and passenger travel, safety, vehicles, economy and finance, and energy and environment. The individual profiles are available in print; some are available on the BTS website or on CDs. BTS also produced State Transportation Profile: Summary 2003, which updates the state data that appears in the initial series. This summary document also includes a description of the data sources used; information on data formats; federal, state, and national data sources; a glossary of terms; and contact information for each state Department of Transportation. BTS plans to update the summary data each year as a new component of NTS.

Raising the general awareness and improving the quality, relevance, and comparability of transportation data and information across North America is the mission of the North American Transportation Statistics Interchange. The Interchange is a collaboration between transportation and statistical agencies of the United States, Canada, and Mexico. BTS, the U.S. Census Bureau, and the U.S. Army Corp of Engineers serve as the lead U.S. agencies. Together these agencies work with Mexico's Ministry of Communications and Transport, Institute of Transportation, and National Institute of Statistics, Geography and Informatics, and with Statistics Canada and Transport Canada to provide information necessary for an efficient and fully integrated transportation system for North America. An initial, key result of the trilateral collaboration was the development of the North American Transportation in Figures report in 2000 [12]. An online North American Transportation Statistics Database will be made publicly available by the end of 2004.

Creating a Forum for Transportation Statistical Research

Advancing statistical methods and standards and ensuring the accuracy, reliability, and relevance of transportation data is a continuing process. It requires the sharing of the latest research among the transportation statistics research community. BTS helps to enable this process with the production and dissemination of a journal and the maintenance and operation of a digital library.

The BTS Journal of Transportation and Statistics (JTS) publishes original research focused on the statistical analysis of transportation. This peer-reviewed international journal encourages the application of advanced statistical methods to transportation problems. As such, JTS supports the work of the community of transportation statisticians-in universities, university transportation centers, research institutes, private research firms, and transportation agencies at the federal, state, and local levels-by providing them with a common venue for the publication of their research. BTS statisticians and analysts also use this flagship publication for dissemination of their advanced research on transportation and to communicate with the transportation statistics community about the statistical characteristics of new BTS datasets.

JTS presents articles that measure and analyze transportation activity and the performance of the transportation system; advance the science of acquiring, validating, managing, and disseminating transportation information; and measure and analyze how transportation interacts with the economy and how it affects the environment.

The completely digital National Transportation Library (NTL) provides a full range of information access services to the transportation community. The collection contains over 12,000 full-text, public research and policy documents covering a wide range of transportation topics, with a focus on USDOT and state DOT publications. NTL services also include reference and referral as well as networking. The broad outreach efforts of the NTL led to the implementation of a union catalog that provides transportation library users with information about the holdings of many regional transportation libraries. Furthermore, the NTL website links users to the Transportation Libraries Catalog (TLCat) website and an internet version of TRB's Transportation Research Information Service (TRIS Online), which gives users free access to almost half a million records of published research on all modes and disciplines in transportation.

Conclusion

The preceding overview shows that accomplishments and work underway are succeeding in filling critical transportation data gaps and providing useful information to the transportation community. While work will always remain to be done, through its own efforts and in collaboration with others, BTS is improving the state of transportation statistics, especially within the focused core areas of freight, passenger travel, air transportation, economic, and geospatial data.

REFERENCES

1. George Mason University, Mercatus Center, 4th Annual Performance Report Scorecard: Which Federal Agencies Inform the Public? 2002, available at http://www.mercatus.org/governmentaccountability/category.php/15.html, as of July 2004.

2. Transportation Research Board, A Concept for a National Freight Data Program, Special Report 276 (Washington, DC: August 2003), also available at http://trb.org/, as of July 2004.

3. U.S. Department of Transportation, Bureau of Transportation Statistics, America on the Go: U.S. Business Travel, October 2003, available at http://www.bts.gov, as of July 2004.

4. ______. America on the Go: U.S. Holiday Travel, November 2003, available at http://www.bts.gov, as of July 2004.

5. ______. Freedom to Travel (Washington, DC: 2003), also available at http://www.bts.gov, as of July 2004.

6. ______. NTAD 2004, CD, (Washington, DC: 2004).

7. ______. Freight Shipments in America (Washington, DC: April 2004), also available at http://www.bts.gov, as of July 2004.

8. ______. Scheduled Intercity Transportation: Rural Service Areas in the United States (Washington, DC: 2004), also available at http://www.bts.gov, as of July 2004.

9. U.S. Department of Transportation, Bureau of Transportation Statistics and Federal Highway Administration, NHTS: Highlights of the 2001 National Household Travel Survey (Washington, DC: 2003).

10. U.S. Department of Transportation, Bureau of Transportation Statistics, Federal Highway Administration, and the Office of Intermodalism, GeoFreight, CD (Washington, DC: 2004).

11. U.S. Department of Transportation, Bureau of Transportation Statistics and National Highway Traffic Safety Administration, National Survey of Pedestrian & Bicyclist Attitudes and Behaviors, no date, available at http://www.bts.gov, as of July 2004.

12. U.S. Department of Transportation, Bureau of Transportation Statistics; U.S. Department of Commerce, U.S. Census Bureau; Statistics Canada; Transport Canada; Instituto Mexicano del Transporte; Instituto Nacional de Estadística, Geografía e Informática; and Secretaría de Comunicaciones y Transportes, North American Transportation in Figures, English Edition BTS00-05 (Washington, DC: 2000), also available at http://www.bts.gov. Spanish edition available in print and on the website. French version available only on the website.

¹ Released in October 2003.

² A TAZ is similar in size to block groups but is specifically designed to fit local planning needs and is defined by individual MPOs for tabulating transportation statistics from the census.

³ See http://www.bts.gov/pdc/index.html , as of July 2004, to view or download this product.

⁴ See U.S. Department of Transportation, Federal Highway Administration, http://www.fhwa.dot.gov/ctpp/dataprod.htm for further information on releases.

⁵ This pilot program is also known as Longitudinal Employer Dynamics (LED).

⁶ These are preliminary data from the 2002 CFS, as discussed earlier. Trucks contributed 41 percent of all ton-miles in 2002 as well as 73 percent of the value of commodities.

⁷ See http://www.bts.gov/mcs/desc.html/ , for more details.

⁸ See http://www.bts.gov/mcs/prod.html for report availability, as of July 2004.

⁹ BTS and the Bureau of Economic Analysis of the Commerce Department found that in-house trucking in 1996, the last year for which this number is available, contributed 1.6 percent of GDP to the economy.

¹⁰ The 1996 data and analysis were presented in Transportation Statistics Annual Report 2000, pp. 142??, available at http://www.bts.gov.

¹¹ NTAD 2004 was produced by BTS in cooperation with FHWA, the Federal Aviation Administration, the Federal Transit Administration, the Federal Railroad Administration, the U.S. Census Bureau, BEA, the Army Corps of Engineers, the National Park Service, and the Military Traffic Management Command Transportation Engineering Agency.

¹² Public Law 106-554, Sec. 515, 114 Stat. 2763 (Treasury and General Government Appropriations Act of 2000).

¹³ See http://dmses.dot.gov/submit/DataQualityGuidelines.pdf.

¹⁴ Previously, several issues of an NTS document were produced by the U.S. Department of Transportation itself.