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23 CFS that can be produced for electronics and electrical equip- After analyzing data availability, the Federal Highway ment, using the table for California. The average value per ton Administration (FHWA) developed the network as a subset for all modes is about $41,000, based on an average of goods of the NHPN, version 3. moving by land with values of approximately $27,000 per ton The FAF highway network not only includes FAF truck and goods of the same commodity moving by air with a value counts, but passenger automobile counts and non-FAF truck of approximately $151,000 per ton. Table 5.2 also shows that counts. Data was obtained from traffic databases in HPMS for many modes the data are not reported because the small and other state sources. After integrating the data sources, the sample size produces unreliable results. FAF network was converted to TransCAD, a proprietary The 1997 CFS is available on CD-ROM from the travel demand model software package. TransCAD allows the U.S. Census Bureau at http://www.census.gov/econ/www/ assignment of daily freight truck trips to routes using stan- cfsmain.html. dard network assignment techniques. The end result was the completed FAF highway network database containing traffic volume, capacities, speeds, locations, and travel times for 5.3 Network Data each road segment. Modeling truck freight movements requires the use of net- The Highway Capacity Dataset contains estimated truck works with physical information about the highway network volumes and system capacities for each road segment on links. The network used in assigning freight flows must the FAF network, obtained through freight demand analy- account for characteristics such as segment capacity, volume, sis. The 1998 freight volume data are included, as well as free flow speed, and travel time. Networks exist for other forecasts for 2010 and 2020. Volume is provided for FAF modes (rail, air, water), but typically do not include infor- trucks, non-FAF trucks, and general traffic. The non-FAF mation to allow the calculation of congestion and route trucks were calculated by subtracting model-assigned choice in the same fashion as truck/highway networks. Many trucks from observed truck counts. Both automobiles and freight shipments use more than one mode in a trip, and data non-FAF trucks were treated as preloaded volumes that on the intermodal terminals where freight can change modes contribute to highway congestion in the FAF route assign- also are required. ment model. Additional attributes such as volume/capacity ratio, delay, and derived speed also are included. The data files are available Modal Networks in either TransCAD or ESRI GIS format, with all the querying National modal networks are needed in statewide freight and mapping capabilities of these two programs. The Federal forecasting, particularly for non-highway modes and for Highway Administration also provides a data dictionary for use highway networks for areas of the United States beyond the in understanding abbreviated column headings in the dataset. area covered by a statewide model. The Bureau of Trans- One layer of the High-Capacity Dataset contains informa- portation Statistics provides attribute information for water- tion on the FAF highway network, linked to information on way and railroad networks, although this information is not each road segment. Figure 5.4 shows the GIS representation compatible with conventional travel demand modeling soft- of U.S. highways on the FAF network. ware. The Oak Ridge National Laboratory has created a mul- Each road segment is described using up to 17 attributes. timodal network to determine distances and routes for the These attributes include length in miles, state and county CFS. However, Oak Ridge uses special software that other identifiers, signs, road name, function class, status, Na- agencies may find difficult to use. A comprehensive source of tional Highway System (NHS) designation, and rural code. network data can be created by matching the network of the In a separate file, the Highway Capacity Dataset contains National Highway Planning Network (NHPN) Geographic freight flow data that can be overlaid on the FAF highway Information Systems (GIS) shapefile with the attribute data network maps. Using GIS software, a user can then identify from the Highway Performance Monitoring System (HPMS) segments with specified levels of congestion, delay, or ca- Data collected by each state. This task already was undertaken pacity. Besides road characteristics, the freight volume data by the FAF and is described below. contained in this file includes annual average daily traffic, FAF/non-FAF trucks, speed, delay, flow, and capacity for both low and high growth estimates in 1998, 2010, and Freight Analysis Framework Highway Capacity 2020. Database The FAF Highway Capacity Database is available from the The FAF road network leverages existing Federal road FHWA at http://ops.fhwa.dot.gov/freight/freight_analysis/ inventories that contain, or can be linked to, HPMS data. faf.