Observed Trip Chain Behavior of Commercial Vehicles

Abstract

Results are presented from a comprehensive analysis of the observed trip chain behavior of commercial vehicles in the Denver, Colorado, region on the basis of data collected by the Denver Regional Council of Governments. These analyses may provide the foundation for further research into commercial vehicle trip chain models. Trip chain behavior is characterized by number of trip chains, length of trip chains, and conditional probability of trip purpose. For this analysis, trip purposes were grouped as freight transportation; transport of people; service calls; fuel, service, and so forth; and return to base or home. Commercial vehicles were grouped as automobile, pickup van, single-unit truck, combination truck, and sports utility vehicle. The conditional probabilities were analyzed for a fixed length of trip chain and were conditioned on stop number. Although most vehicles were found to make one trip chain per day, one of four commercial vehicles made more than one trip chain per day. The analyses also indicated that the average number of stops per trip chain decreased with the number of trip chains. About 35% of the trip chains involved two stops, although some trip chains had more than 12 stops. The main trip purpose for all commercial vehicles was freight transportation, although some vehicles had mixed uses. This study apparently represents the first comprehensive attempt reported in the literature to analyze the observed patterns of commercial vehicle trip chain behavior.