Alternative Definitions of Passing Critical Gaps

摘要

In most countries a substantial proportion of the road network is two-lane highways.Available gaps for passing are fundamental element in the operation of two-lanehighways. Providing passing opportunities are important in order to reduce the formationof vehicle platoons in the traffic flow, increase the level of service and increase safety. Italso impacts fuel consumption and emissions. Despite the importance of passing on twolane highways, few studies focused on exploring passing gap definitions when modelingpassing behavior.This research investigates different definitions of passing gaps and uses these definitionsto develop different passing gap-acceptance models. Three different models weredeveloped and calibrated based on data on passing maneuvers collected with a drivingsimulator. The generic structure of these models is composed of the drivers' desire to passand their gap-acceptance decisions. Impact of traffic characteristics, road geometry anddriver characteristics were included in these models.The results show that there is a significant impact of the passing gap definition on themodels’ capability to explain drivers’ passing behavior. Moreover, the estimation resultsshow that modeling the drivers' desire to pass the vehicle in front has a statisticallysignificant contribution in explaining their passing behavior. Various variables thatcapture the impact of the traffic conditions, geometric characteristics of the road section,driver’s characteristics and the unobserved heterogeneity in the driver population werefound to have a significant impact on the drivers’ desire to pass and their gap-acceptancedecisions.