Vehicle Merging Model for Acceleration Lane under Condition of Changeable Critical Headway

Considering the vehicles' changeable critical headway when driving along the acceleration lane of an on-ramp,a vehicle merging model was proposed using differential method.This model well considered the effect of roads geometry characteristic and major road traffic conditions on driver's merging behavior. It also revealed the regularity of the effect of length of acceleration lane and traffic flow of main road shoulder lane on the merging probability.The numerical result shows that(1) When the lane has a lower traffic flow,drivers are easily to find a merging opportunity near the beginning of the acceleration lane;while a lager traffic flow arrives,the merging probability near the nose section will be significantly reduced.(2) The drivers' tendency to merge will reduce along with the increase of acceleration lane length,and the merging probability decreases at the same site.