Freight transportation has recently been pushed to the forefront of transportation planning by the confluence of several significant trends. Economic globalization, electronic commerce and the Internet are profoundly changing the geographic realm and the features of economic markets. Just In Time production systems are stressing the importance of freight systems as conveyors of high priority goods. Increased awareness among community leaders, environmental professionals and legislators about the health effects of truck traffic pollution is adding pressure for an enhanced consideration of freight transportation as part of the transportation planning process.