Urban Trip Distribution Friction Factors

摘要

This report documents work done by the Urban Planning Division in summerizing study reports available on trip distribution. The mathematical travel model most often used to distribute travel throughout an urban region in the United States is called the Gravity Model. For transportation planning purposes, the friction factor or traveltime factor is normally calibrated from origin-destination data. Friction factors express the effect that spatial separation exerts on trip interchange. They indicate the impedence to interzonal travel due to seperation between zones. In effect, these factors measure the probability of trip making at each time (usually one minute) increment of traveltime.