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9 FAF. The FAF has recently been reviewed by the TRB Com- available for the National Rail Network. Networks are avail- mittee on the Future of the FHWA's Freight Analysis Frame- able by state, and are obtainable from the BTS on the National work (Meyburg 2004). Transportation Atlas Database CD-ROM. This CD-ROM also contains the U.S. Army Corps of Engineers Navigable Waterway Network, hydrographic features, fixed-guideway Census Transportation Planning Package transit networks, runways, seaports, Amtrak stations, airports, intermodal terminals, and jurisdictional boundaries. The Census Transportation Planning Package (CTPP) is a special tabulation of the decennial census that reports data by traffic analysis zone (TAZ), both rural and urban. By analy- Railroad Carload Waybill Sample sis of the journey-to-work questions, the CTPP provides in- formation on home-to-work flows, modes of travel to work, Railroads doing business of more than 4,500 carloads per ridesharing to work, vehicle availability, commute times, and year are required to submit a sample of their waybills to the employment counts at the workplace. Demographic data are Surface Transportation Board. Waybills contain information tabulated by both place of work and place of residence. The on origin and destination points, type of commodity, number CTPP is a valuable source of information about employment of cars, tons, revenue, length of haul, participating railroads, in the workplace by industrial sector and is available on CD- interchange locations, and cost. Publicly available data from ROM from the BTS. CTPP is usually available approxi- the sample are geocoded to Bureau of Economic Analysis mately 4 years into the decade. More information may be (BEA) regions; however, commodities are reported to five- found at http://www.fhwa.dot.gov/ctpp/. digit STCC. The 2002 sample contains information on nearly 600,000 shipments from 66 railroads. The confidential data are available to a single point of contact with a state govern- Public Use Microdata Sample ment, often an agency that regulates railroads; therefore, it is possible for a state department of transportation (DOT) to The Public Use Microdata Sample (PUMS) is an output of the gain access to data with precise geocoding. Strict rules apply decennial U.S. Census. The sample contains 5% of all house- to disseminating data outside of state government. Data hold records from the long form that have been cleaned of any within the waybill about revenue from a shipment are con- identification and geocoded coarsely to special zones called sidered to be inaccurate by the Surface Transportation Board. PUMAs (Public Use Microdata Areas), which are areas with at least 100,000 persons. PUMS allows special tabulations that are not normally available for a metropolitan area, county, or COMMERCIAL DATABASES AND FORECASTS state. Many planning agencies use PUMS to understand IN USE BY STATES household structure when building trip generation models. The following commercial databases and forecasting ser- vices were specifically mentioned by states when answering ES-202 questions about their models. This section is included to am- plify on state responses and is not intended to be a compre- ES-202 is a cooperative program where states report infor- hensive listing or review of such databases. mation on employment that is derived from the states' un- employment insurance programs to the federal government. ES-202 data can provide employment at the workplace by in- Reebie TRANSEARCH dustrial category; however, federal rules dictate that the con- fidentiality of the data must be respected. The quality of the Reebie can supply data on multimodal commodity flows be- data and the ways in which it is administered differ across tween locations in the United States at a greater level of spa- states. As with all secondary sources of employment data, the tial detail than the CFS. Reebie integrates data from both geocoding of work locations requires considerable cleaning public and proprietary data sources. and verification. The most serious problem for travel fore- casting is that the mailing addresses of employers do not nec- Commercial Demographic Forecasts essarily agree with the addresses of the actual workplaces. ES-202 data may be available from a state's labor or em- Companies such as Global Insight (formerly WEFA and ployment agency. The data set is continuously updated. DRI) and Woods & Poole can provide economic and demo- graphic forecasts by county. Similar forecasts may be avail- able for certain states through universities or state agencies. National Networks The National Highway Planning Network is available as geo- Commercial Employment Databases graphic information system (GIS) layers and contains a topological description of 450,000 mi of arterial highways in D&B (formerly Dun and Bradstreet) maintains a compre- the United States. A similarly comprehensive GIS database is hensive database of U.S. companies and their characteristics.