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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - March/April 2005

March/April 2005
Issue No:
Vol. 68 No. 5
Publication Number:
Table of Contents

Internet Watch

Data, Data Everywhere

by Keri A. Funderburg

In recent years, the United States has become an increasingly data-driven society. The Internet, new database software, and powerful personal computers, personal data assistants, and even cell phones have provided researchers, engineers, and policymakers with a world of new information at their fingertips. Transportation professionals now can access numerous databases and mapping systems simply by logging onto their computers or other handheld devices. The following are just a few of the new data tools that have become available:

Putting Transportation on the Map

Transportation engineers and researchers frequently must transform diverse technical information into an efficient, easy-to-understand format. One way they can do this is by mapping data using a geographic information system (GIS). These systems of computer hardware and software are capable of collecting, storing, analyzing, and disseminating information about the location of natural and manmade features in various areas worldwide. Recently, the U.S. Department of Transportation's (USDOT) Bureau of Transportation Statistics (BTS) published the 2004 version of its National Transportation Atlas Database (NTAD 2004), a set of nationwide geographic databases that include information on transportation facilities and networks, along with associated infrastructure.

Each NTAD database is supported by metadata documentation, as prescribed by the Federal Geographic Data Committee. New features in NTAD 2004 include updated transportation facilities, U.S. Environmental Protection Agency nonattainment areas, updated intermodal terminals, and an updated road and rail network. Each dataset is presented in shapefile format, a data structure compatible with most GIS software packages.

"NTAD fulfills part of BTS's goal of providing high-quality data and services pertaining to all modes of transportation," says Roger Lotz, a public affairs specialist at BTS. "The data support research, analysis, and decisionmaking and are useful to professionals within all levels of government. For example, the U.S. Department of Defense currently is using NTAD data as a core piece of its infrastructure data inventory."

The data used to compile NTAD 2004 were provided by USDOT and other agencies. The 2004 version is available from BTS in a two-disk CD-ROM set. For more information, visit /pdc/user/products/src/products.xml?p=1802&c=5.

A Topnotch Performance

Since 1978, the Federal Highway Administration (FHWA), State highway agencies, local governments, and metropolitan planning organizations (MPOs) have worked together to collect, assemble, and report data for the FHWA Highway Performance Monitoring System (HPMS), a database that includes information reflecting the extent, condition, performance, use, and operating characteristics of the Nation's highways. According to Robert Rozycki, transportation specialist at FHWA, prior to the development of the HPMS database, Congress and transportation agencies relied only on ad hoc road studies to obtain information on highway performance because a central database of information on the Nation's roads did not exist. HPMS, however, includes limited data on all public roads, more detailed data for a sample of the Nation's arterial and collector road systems, and summary information for many urbanized, small urban, and rural areas.

HPMS serves the needs of State, MPO, local government, and other transportation officials for assessing highway conditions, air quality trends, and future investment requirements. The data also are used to assess the performance of the highway system under FHWA's strategic planning process and to apportion Federal-aid funds.

To learn more and download data from HPMS, visit

The FHWA "Highway Performance Monitoring System" Web site.

Making it Personal

Transportation professionals also need to know about the people who use the roadway system. One database containing this information is the National Household Travel Survey (NHTS), a USDOT effort sponsored by BTS and FHWA to collect data on both long-distance and local travel by the American public.

NHTS includes trip-related data fields, such as mode of transportation; duration, distance, and purpose of trip; and demographic, geographic, and economic data. Policymakers, State DOTs, MPOs, industry professionals, and academic researchers frequently use such data to gauge the extent and patterns of travel, to plan new investments, and to better understand the potential implications of those investments for the Nation's transportation infrastructure. The most recent version of NHTS, from 2001, updates information gathered by two series of previous surveys—the Nationwide Personal Transportation Surveys conducted in 1969, 1977, 1983, 1990, and 1995 and the American Travel Surveys conducted in 1977 and 1995.

"The first survey in this series was conducted in 1969 because the States were discontinuing their reports on automobile use," explains NHTS Project Manager Susan Liss with FHWA. "USDOT saw the need for this type of data, and the fact that the survey has been conducted periodically ever since reinforces the utility and extensive uses of this dataset."

Internet users can access the complete sets of the 2001 NHTS data and find user-friendly analysis tools at The site also features a comprehensive inventory of publications using the 2001 NHTS data, helpful tips for using the database, a mailing list for users to exchange ideas and information pertinent to NHTS, and links to related Web sites.

Home Sweet Home for Data

Although most transportation databases, including those discussed here, have their own Web sites, the "TranStats" Web site ( provides a central location for users to find out about all of the transportation Web sites available from USDOT. TranStats offers researchers and analysts a one-stop shop for transportation data.

TranStats aims to streamline the data collection process and offers several helpful features, including a searchable index of more than 100 transportation-related databases, online data documentation, and an interactive mapping feature to help with visualizing geographic data. A selective download feature enables users to choose variables of interest and download data directly to their computers using any database, spreadsheet, or statistical package.

The Bureau of Transportation Statistics' "TransStats" Web site.