Skip to Main Content

Literature Searches and Literature Reviews: Resources: Where to Search

Resources: Where to Search

Below are bibliographic databases, research databases, data and statistics resources, directories and websites to assist your search.

Bibliographic Databases

ABI/INFORM (ProQuest) Business research. Provides full-text journals, business press and trade publications. Subjects: businesses, commodities, freight service, industries, markets. Fee-based.

Academic Search Complete (EBSCO) Multidisciplinary. Indexes 11,000 peer-reviewed journals and trade publications. Subjects: aviation, planning, transportation. Fee-based.

Aerospace Research Central (American Institute of Aeronautics and Astronautics) Aerospace technology, engineering and science. Indexes all AIAA meeting papers published since 1963 and journal articles since 1996. Subjects: aerospace engineering, aviation, materials. Fee-based.

ASCE Library (American Society of Civil Engineers) Civil engineering. Indexes and provides full-text access to all 33 ASCE journals (1983 to present), conference proceedings (2000 to present), standards, and e-books. Includes topical special collections. Subjects: bridges, construction, environment, harbors, highway engineering, materials, pavements, pipelines, transportation, tunnels. Fee-based.

Civil Engineering Database (American Society of Civil Engineers) Provides access to indexes of ASCE journals, conference proceedings, standards and e-books. Subjects: bridges, construction, environment, harbors, highway engineering, materials, pavements, pipelines, transportation, tunnels. Free.

Engineering Village (Elsevier)  All engineering disciplines. Indexes more than 5,000 journals as well as conference papers and technical reports; includes millions of bibliographic citations and abstracts. Subjects: bridges, construction, environment, highway engineering, traffic engineering, transportation. Fee-based.

Environmental Sciences and Pollution Management (ProQuest) Indexes more than 10,000 journals, conference proceedings, technical reports and books on air quality, energy resources and other topics. Includes environmental impact statements. Subjects: energy, environment, pollution, safety. Fee-based.

ERIC Database (U.S. Department of Education, ProQuest) Primarily education. Indexes books, journals, reports, proceedings, statistical data, tests and dissertations. Subjects: bicycling, cyclists, pedestrians, school buses, schoolchildren, school safety. Free.

FRA eLibrary (Federal Railroad Administration) Provides access to accident, safety, litigation and compliance reports; technical and environmental reports; conference papers; press releases; and policy and guidance documents. Subjects: freight and passenger service, railroads, railroad safety, rail transportation, regulation. Free.

Google ScholarMultidisciplinary. Retrieves articles, theses, books and abstracts from academic publishers, professional societies, online repositories, universities and other websites. Some records include links to related articles and to other sources that cite the item. Subjects: energy, environment, planning, safety, transportation. Free.

IEEE Xplore (Institute of Electrical and Electronics Engineers) Electrical engineering, computer science and electronics. Indexes 160 journals; 1,200 conference proceedings; and more than 3,800 technical standards published by IEEE. Subjects: control (electronic), information systems, information technology, intelligent transportation systems, vehicle electronics. Fee-based.

Inspec (Clarivate) Electrical engineering, electronics, computer science. Indexes more than 4,300 journals and other serial titles; 3,000 conferences, books, reports and dissertations. Subjects: control, information systems, information technology, intelligent transportation systems, traffic engineering, vehicle electronics. Fee-based.

LexisNexis (LexisNexis) News and business, legal and reference information. Provides full-text access to hundreds of U.S. and foreign newspapers, legal and business publications, wire services, transcripts and trade publications. Subjects: businesses, commodities, freight service, industries, legislation and regulation, logistics, markets, news, policy, trade. Fee-based.

National Technical Information Service (NTIS)National Technical Reports Library (NTRL) (U.S. Department of Commerce) Multidisciplinary. NTIS contains records for more than 3 million technical reports (800,000 with full-text links) from government agencies including the U.S. DOT and the U.S. Department of Energy. Full-text reports can be downloaded free of charge and hard copies of all reports can be purchased. NTRL offers subscription-based access to NTIS indexes, abstracts and technical reports. Subjects: aviation, energy, engineering, environment, pavements, transportation. Free.

National Transportation Library - ROSA P. (U.S. DOT, Bureau of Transportation Statistics) Database of electronic resources including full-text research and technical reports from U.S. DOT, state DOTs and university transportation centers. Provides access to research and policy sites. Subjects: air transportation, construction, highways, maintenance, policy, public transit, railroad transportation, safety, transportation, water transportation. Free.

ProQuest Dissertations and Theses (ProQuest) Citations to more than 3 million dissertations and theses and 1 million full-text reports. Subjects: communications and control, construction, energy, engineering, environment, planning and design, safety and security, transportation operations. Fee-based.

PsycInfo (American Psychological Association) Provides information about psychological aspects of disciplines such as medicine, education, business and law. Subjects: alcohol use, behavior, distraction, drivers, drug use, human factors, perception. Fee-based.

PubMed/MEDLINE (U.S. National Institutes of Health, National Library of Medicine) Biomedicine. Indexes 5,600 journals and includes more than 19 million citations. Subjects: alcohol use, anatomy, biophysics, distraction, drivers, drug use, human behavior, human factors, injuries, perception. Free.

SAE MOBILUS Digital Library (Society of Automotive Engineers) Automotive–vehicle and aerospace engineering. Indexes technical papers, standards, e-books and other material from SAE International and other providers. Subjects: aerospace engineering, automotive engineering, vehicle electronics. Fee-based.

SafetyLit (World Health Organization, San Diego State University) Indexes reports from 30 professional disciplines relevant to preventing unintentional injuries including economics, engineering, ergonomics and human factors, health and medicine, law and law enforcement, and psychology. Subjects: crashes, ergonomics, human factors, injuries, law enforcement, safety. Free.

ScienceDirect (Elsevier) Multidisciplinary. Indexes more than 2,200 peer-reviewed journals published by Elsevier in the sciences and engineering. Subjects: energy, environment, highways, railroads, safety, transportation. Fee-based.

Scopus (Elsevier) Multidisciplinary. Covers journals, patents and websites from more than 5,000 publishers. Indexes more than 25,000 science, medical, technical and social science peer-reviewed titles. Provides citation and cited-reference searching. Subjects: aviation, energy, engineering, environment, highway engineering, human factors, planning, safety, traffic engineering, transportation. Fee-based.

TRB Publications Index (TRB) Indexes of papers, articles and reports published by the Transportation Research Board, the Highway Research Board, the Strategic Highway Research Program and related programs. Subjects: air transportation, construction, highways, maintenance, policy, public transit, railroad transportation, safety, transportation, water transportation. Free.

TRID, TRB and ITRD (TRB, International Transport Forum) World’s largest and most comprehensive bibliographic database for transportation. Contains more than 1.3 million records of published research and ongoing research projects. Covers peer-reviewed journals, research and technical reports; papers from conference proceedings; trade publications; environmental impact statements; and books. Provides links to more than 120,000 full-text reports, papers and articles. Includes all modes and aspects of transportation. International in scope with 400,000 records from European sources. Subjects: air transportation, construction, highways, maintenance, policy, public transit, railroad transportation, safety, transportation, water transportation. Free.

US Newsstream (ProQuest) Current U.S. news content, as well as archives that stretch back into the 1980s. Includes top newspapers, wires, broadcast transcripts, blogs and news sites in full-text format. Subjects: businesses, markets, news. Fee-based.

Web of Science (Clarivate) Multidisciplinary. Indexes more than 5,000 peer-reviewed journals in the sciences, social sciences, arts and humanities. Includes Science Citation Index, providing searching of footnoted citations. Subjects: aviation, bridges, construction, energy, environment, highway engineering, human factors, planning, safety, traffic engineering, transportation. Fee-based.

Data and Statistics

Annual Energy Review (U.S. Department of Energy, Energy Information Administration) Reports annual energy statistics beginning with 1949. Includes data on total energy production, consumption and trade; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, international energy, and financial and environmental indicators. Subjects: energy, environment, fuel consumption. Free.

Boating Safety Resource Center (U.S. Coast Guard) Provides statistics on all reported recreational boating safety accidents and incidents throughout the United States and its territories. Subjects: safety, ships, water transportation. Free.

Bureau of Transportation Statistics (U.S. Department of Transportation) Provides comprehensive coverage of all modes of transportation data, statistical analysis and abstracts. Subjects: aviation, crashes, drivers, freight transportation, highway travel, rail, transportation modes, transportation operations. Free.

Census Transportation Planning Products (CTPP) (FHWA) A set of special tabulations from decennial census demographic surveys designed for transportation planners. Uses large sample size to provide reliable and accurate data. Subjects: census, persons and personal characteristics, transportation operations. Free.

Commodity Flow Survey. (U.S. DOT, Bureau of Transportation Statistics) Primary source of national- and state-level data on domestic freight shipments by American establishments in mining, manufacturing, wholesale, auxiliaries and selected retail industries. Provides data about the types, origins and destinations, values, weights, modes of transport, distance shipped and ton-miles of commodities shipped. Subjects: commodities, freight transportation, hazardous materials, trade. Free.

Congestion Data for Your City (Texas Transportation Institute) Provides basic statistics and ranking for urban areas in categories of travel delay, excess fuel consumed, truck congestion cost and total congestion cost with comparisons back to 1982. Detailed information is provided on spreadsheets for 101 cities. Subjects: commuting, drivers, freight transportation, fuel consumption, traffic congestion. Free.

Corporate Average Fuel Economy (CAFE) (U.S. DOT, NHTSA) Includes links to reports on fuel economy performance of vehicle fleet. Subjects: environment, fuel consumption, vehicles. Free.

Data.gov (U.S. General Services Administration) Site of U.S. government’s open data portal. Provides comprehensive coverage of over 20 topics, including climate, geospatial, public safety, and over 90,600 data sets. Include federal, state and local data, resources, and tools. Subjects: crashes, drivers, environment, highway safety, injuries, safety. Free.

Data Sources Related to Freight Transportation (U.S. DOT, FHWA) Includes links to information on highway, maritime, rail and pipeline modes, product information and road classification. Subjects: freight transportation, highway travel, trade, transportation modes. Free.

 

Estimating Information: Average Low Bid Unit Prices Texas Department of Transportation) Includes average low unit bid prices for highway construction and maintenance projects statewide and by district. Subjects: construction, economic and social factors, road construction. Free.

Fatality Analysis Reporting System (NHTSA) Provides annual data regarding fatal injuries in motor vehicle traffic accidents; allows user to run customized queries. Subjects: alcohol use, bicyclists, crashes, distraction; drivers, fatalities, highway safety, injuries, safety. Free.

Federal Aviation Administration Data and Research (FAA) Provides data on accidents and incidents, safety, passengers, cargo, commercial space, funding and aviation forecasts. Subjects: aircraft crashes, aviation, safety.

Federal Motor Carrier Safety Administration: Data, Analysis and Statistics (U.S. DOT, Federal Motor Carrier Safety Administration) Provides access to safety ratings and crash statistics for commercial trucks and buses in tables and reports. Subjects: buses, crashes, freight transportation, hazardous materials, motor carriers, safety. Free.

Federal Railroad Administration: Office of Safety Analysis (Federal Railroad Administration) Provides data files on railroad safety information, including accidents and incidents, inspection and highway–rail crossing data. Subjects: freight transportation, rail, safety. Free.

Freight Analysis Framework (U.S. DOT, FHWA) Integrates data from a variety of sources to create a comprehensive picture of freight movement among states and major metropolitan areas. Provides estimates for tonnage and value, by commodity type, mode, origin and destination. Subjects: commodities, freight transportation, trade, transportation operations. Free.

Highway Safety Information System (U.S. DOT, FHWA, Turner Fairbank Highway Research Center) A multistate database that contains crash, roadway inventory and traffic volume data for a select group of states. Participating states were selected based on the quality and quantity of data available and ability to merge data from various files. Subjects: crashes, drivers, highway safety, road construction. Free.

Highway Statistics (U.S. DOT, FHWA) Provides analyzed statistical data on motor fuel, motor vehicles, driver licensing, highway-user taxation, state and local government highway finance, highway mileage and federal aid for highways. Site includes a historical archive back to 1945. Subjects: drivers, fatalities, finance, highway travel, taxation. Free.

IHS Maritime Data Services (IHS) Databases cover ship movements, ship characteristics, ownership, maritime companies, ports and terminals. Includes news archive and image bank. Subjects: harbors, shipping, ships, transit, water transportation. Fee-based.

Journey to Work and Place of Work (U.S. Census Bureau) Includes data on means of transportation to work, travel time to work, time leaving home to go to work, private vehicle occupancy and travel to work characteristics. Subjects: behavior, commuting, highway travel, transportation operations. Free.

Life-Cycle Benefit/Cost Analysis Model (California Department of Transportation) Life-cycle benefit–cost analysis for proposed projects performed using Cal-B/C, a PC-based spreadsheet model. Analyzes many types of state highway and public transit construction and operational improvement projects. Subjects: construction, economics, finance, road construction. Free.

Measurement of Government Transportation Financial Statistics (U.S. DOT, Bureau of Transportation Statistics) Consists of transportation revenues and expenditures for federal, state and local governments. Contains data by revenue source, expenditure type and mode. Subjects: economics, finance. Free.

Monthly Energy Review (U.S. Department of Energy, Energy Information Administration) Includes total energy production, consumption and trade; energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy and international petroleum; carbon dioxide emissions; and data unit conversions values. Subjects: energy, greenhouse gases, trade. Free.

Motor Carrier Management Information System (U.S. DOT, Federal Motor Carrier Safety Administration) Provides information on the safety fitness of commercial motor carriers and hazardous material shippers subject to the Federal Motor Carrier Safety Regulations and the Hazardous Materials Regulations. Subjects: hazardous materials, motor carriers, safety, shipping. Free.

Motor Vehicle Accidents and Traffic Fatalities U.S. Census Bureau. Data from U.S. Census Bureau on transportation motor vehicle accidents and fatalities from statistical abstract. Subjects: crashes, distraction, drivers, fatalities, injuries, safety. Free.

National Automotive Sampling System (U.S. DOT, NHTSA) Composed of two systems, the Crashworthiness Data System (CDS) and the General Estimates System (GES), and based on cases selected from a sample of police crash reports. Provides data on passenger vehicle crashes to identify potential improvements in vehicle design. GES data focus on the overall crash picture and trends. Subjects: crashes, highway safety, injuries, safety. Free.

National Bridge Inventory Database (U.S. DOT, FHWA) Provides data tables from the National Bridge Inventory identifying bridges by new construction and rehabilitation, state and county, condition, deficiencies, deck type, year of construction and other factors. Subjects: bridges, structural health monitoring. Free.

National Emissions Inventory (NEI) Air Pollutant Emission Trends Data (U.S. Environmental Protection Agency) Presents the estimate of national emissions of the criteria air pollutants. Emissions of pollutants are estimated for many different source categories, collectively accounting for all anthropogenic emissions. Subjects: environment, greenhouse gases, pollutants. Free.

National Household Travel Survey (U.S. DOT, FHWA) National data on the travel behavior of the American public. Allows for analysis of daily travel by all modes, characteristics of the people traveling, their household and their vehicles. The 2009 NHTS updates information gathered in the 2001 NHTS and in prior Nationwide Personal Transportation Surveys. Subjects: behavior, commuting, persons and personal characteristics, transportation modes. Free.

National Transit Database (U.S. DOT, FTA) Information and statistics on more than 660 transit systems in the United States, including operational characteristics, services characteristics, capital revenues and assets, and financial operating statistics. Subjects: buses, rail, transit, transportation modes. Free.

National Transportation Atlas Database (U.S. DOT, Bureau of Transportation Statistics) Set of nationwide geographic databases of transportation facilities, networks and associated infrastructure. These datasets include spatial information for modal networks and intermodal terminals. Metadata documentation, as prescribed by the Federal Geographic Data Committee, is provided for each database. Subjects: transportation modes, transportation operations. Free.

National Transportation Safety Board (NTSB) The NTSB is an independent federal agency charged by Congress with investigating every civil aviation accident in the United States and significant accidents in other modes of transportation–railroad, highway, marine and pipeline. Subjects: aircraft crashes, aviation, highway safety, pipelines, rail, safety, water transportation. Free.

National Transportation Statistics (U.S. DOT, Bureau of Transportation Statistics) Statistics on the U.S. transportation system, including its physical components, safety record, economic performance, the human and natural environment, and national security. More than 260 data tables plus data source and accuracy statements. Internet edition is updated quarterly. Subjects: economic and social factors, environment, safety, transportation operations. Free.

State Data System (SDS) (U.S. DOT, NHTSA) While the Fatality Analysis Reporting System (FARS) has fatal crash data, SDS includes valuable data on injury and property-damage-only crashes. Consists of census data taken from police accident reports. Subjects: crashes, drivers, highway safety. Free.

State Traffic Safety Information (U.S. DOT, NHTSA) Data by state on traffic fatality totals, rates, alcohol involvement, restraint usage, types of vehicles and persons, crash type. Subjects: crashes, drivers, highway safety, safety. Free.

State Transportation Statistics (U.S. DOT, BTS) Statistical profile of state transportation infrastructure. Freight movement, passenger travel, system safety, vehicles, and transportation-related economy and finance, energy usage and environment. Subjects: economic and social factors, environment, transit, transportation modes, transportation operations. Free.

Statistical Abstracts of the United States (U.S. Census Bureau) Comprehensive summary of statistics on the social, political and economic organization of the United States and a guide to sources of other data from the Census Bureau, other federal agencies and private organizations. Subjects: census, economic and social factors, persons and personal characteristics. Free.

Transportation Energy Data Book (U.S. Department of Energy Office of Energy Efficiency and Renewable Energy) Statistics and information that characterize transportation activity with data on factors that influence transportation energy use. Chapters focus on petroleum, energy, highway vehicles, light vehicles, heavy vehicles, alternative fuel vehicles, fleet vehicles, household vehicles, nonhighway modes, transportation and the economy, greenhouse gas emissions and criteria pollutant emissions. Subjects: environment, fuel consumption, greenhouse gases, pollutants. Free.

Transportation Statistics Annual Report (U.S. DOT, BTS) Presents data and information about the performance and impacts of the U.S. transportation system. Topics include traffic flows for all modes; travel times and measures of congestion; transportation costs; availability and use of mass transit; consequences of transportation for the environment; and the extent, connectivity and condition of the transportation system. Subjects: economic and social factors, environment, finance, safety, transportation, transportation modes. Free.

TranStats (U.S. DOT, BTS) Provides comprehensive data sets by agency, mode and subject. Subjects: economic and social factors, environment, safety, transportation, transportation modes, transportation operations. Free.

Urban Mobility Information (Texas A&M Transportation Institute) Provides mobility and congestion data on freeways and major streets for 100 urban areas. Includes annual Urban Mobility Report and Congested Corridors Report along with summary data tables and description of methodologies. Subjects: commuting, highway travel, traffic congestion. Free.

Waterborne Commerce Statistics Center (U.S. Army Corps of Engineers, Navigation Data Center) Includes internal U.S. waterway monthly tonnage; container traffic for U.S. ports, all 50 states and U.S. territories; and waterborne commerce of the U.S. waterways and harbors. Subjects: commodities, harbors, shipping, water transportation. Free.

Websites

Association of American Railways (AAR) Statistics on U.S. and Canadian freight railroads, including Class I performance measures, cost indices and time indicators. Some data are free; cost indices, analyses and freight commodity statistics are fee-based. Subjects: freight traffic, railroad transportation, railroads. Free and fee-based.

Center for Local Aid Support (FHWA)  Provides practical, technical and training-related information for the transportation workforce. Subjects: innovation and technology in transportation. Free.

Context Sensitive Solutions (FHWA) Links to information on context-sensitive solutions and design. Subjects: context sensitive design, highway design, planning. Free.

Council of State Governments Knowledge Center (Council of State Governments) Provides a variety of types of information that focus on issues related to state governments. Subjects: legislation, public policy, state government. Free.

Deer-Vehicle Crash Information Clearinghouse (Iowa State University Institute for Transportation) A pooled fund project to expand the data collection, research evaluation and information exchange on deer–vehicle crashes. Subjects: deer, roadside fauna. Free.

International Air Transport Association (IATA) Aviation economics and operations. Provides data and analysis of economics and policy affecting the global performance of the airline industry. Subjects: airlines, airports, economics, international airports, international transportation. Free.

ITE Technical Resources (Institute of Transportation Engineers) Provides links to websites related to traffic calming, context-sensitive design, pedestrians and connected vehicles. Subjects: context-sensitive design, highway design, traffic engineering, transportation engineering. Free.

National Rural Transit Assistance Program (RTAP) (Federal Transit Administration) Provides support and resources in rural transit-related materials, including training modules, reports and technical briefs. Subjects: education and training, transit, tribal government. Free.

National Work Zone Safety Information Clearinghouse (Texas A&M Transportation Institute) A comprehensive information resource on roadway construction zone safety funded by FHWA. Subjects: construction safety, work zone safety, work zone traffic control. Free.

Pedestrian and Bicycle Information Center (FHWA, University of North Carolina Highway Safety Research Center) Provides information and training to diverse audiences about health and safety, engineering, advocacy, education, enforcement, access and mobility as it relates to pedestrians and bicyclists. Subjects: bicycles, bicyclists, cycling, nonmotorized transportation, pedestrians, walking, walkways. Free.

Science.gov (Commerce, Energy, NASA, Defense Information Managers Group (CENDI)) Provides access to over 55 databases and over 2,100 selected websites from 15 federal agencies, offering 200 million pages of authoritative U.S. government science information including research and development results. Subjects:energy, engineering, environment, policy, science, technology. Free.

Transportation and Climate Change Clearinghouse (U.S. DOT) A one-stop source of information on transportation and climate change issues. Includes information on greenhouse gas (GHG) inventories, analytic methods and tools, GHG reduction strategies, potential impacts of climate change on transportation infrastructure and approaches for integrating climate change considerations into transportation decision making. Subjects: climate change, environmental impacts, environmental policy, environmental protection, environmental quality. Free.

U.S. DOT Maritime Administration (U.S. DOT) Fleet and trade statistics for water transportation in the United States. Subjects: shipping, ships, water transportation. Free.

U.S. DOT Pipeline and Hazardous Materials Safety Administration (U.S. DOT)  Data, statistics and reports on pipelines and the movement of hazardous materials in the United States. Also links to reports, statutes and other documents. Includes the National Pipeline Mapping System. Subjects: hazardous materials, mapping, pipelines, pipeline safety. Free.

Research Databases

Federal Aviation Administration Data and Research (FAA) Provides accident and incident reports; aviation data and statistics; data on safety, passengers and cargo; commercial space data; funding and grants; and aviation forecasts. Subjects: airlines, airport operations, air traffic, air traffic control, air transportation, air transportation policy, passenger service. Free.

Research in Progress (TRB) Provides access to a database of current and recently completed research projects from the U.S. DOT, state DOTs, universities, TRB and international organizations. Subjects: air transportation, construction, highways, maintenance, policy, public transit, railroad transportation, research projects, safety, transportation, water transportation. Free.

Research Need Statements (TRB) Provides access to a database of research needs developed by TRB Technical Committees. Subjects: air transportation, construction, highways, maintenance, policy, public transit, railroad transportation, research management, research projects, safety, transportation, water transportation. Free.

Transport Research and Innovation Monitoring and Information System (BILAT USA 4.0) This project enhances cooperation of research and innovation activities between the European Union (EU) and the United States (U.S.), specifically to encourage interactions between EU and U.S. researchers and innovators, support the improvement of research and innovation framework conditions, provide analyses for decision making, and coordinate policies and programs. Subjects: automation, highway infrastructure, intelligent transportation systems, road safety, urban logistics. Free.

U.S. DOT Research Hub (U.S. DOT) Provides access to a database of projects funded by 10 U.S. DOT agencies, including links to research reports and other products generated by completed projects. Subjects: federal government, research projects, research management. Free.

Directories

AASHTO Committees (American Association of State Highway and Transportation Officials) Much of AASHTO’s work is done by committees comprising volunteer state DOT personnel. AASHTO provides a forum for consideration of transportation issues and conducts surveys, provides data and testifies before Congress on transportation legislation. Subjects: directories, professional personnel, specialists. Free.

Federal Highway Administration Research Expertise Directory (FHWA Turner–Fairbank Highway Research Center) The expertise of TFHRC scientists, engineers and support staff at 20 laboratories and data centers encompasses more than 100 transportation-related disciplines and expertise areas. Subjects: directories, professional personnel, specialists. Free.

Transportation Research Board Online Directory (TRB). The TRB Online Directory provides access to points of contact and information on TRB’s standing committees, project-based committees and panels, and governing committees, as well as to lists of TRB sponsors, affiliates and representatives. In addition, the directory provides password-controlled access to contact information on TRB’s more than 7,000 volunteers. Subjects: directories, professional personnel, specialists. Free.