VEHICLE GAP ACCEPTANCE BEHAVIOUR CONSIDERING CLEARING TIME AT A SELECTED ROUNDABOUT INTERSECTION IN DHAKA CITY FOR HETEROGENEOUS TRAFFIC CONDITION IN BANGLADESH

In this paper vehicle gap acceptance behaviour has been analyzed at a selected roundabout intersection in Dhaka city for the traffic condition in Bangladesh. Traditional gap acceptance measuring methods like Raff method are not effective for the traffic condition of Bangladesh. Consideration of clearing time in gap acceptance study provides a solution to this problem. In this paper gap acceptance behaviour has been study in both traditional Raff method and considering clearing time at particular conflict point in SAARC Fountain intersection. Necessary data for this study was collected from a video recording and the number of accepted gap, accepted lag and clearing of vehicles were counted manually from the video. Critical gap from Raff method was found to be 2.82 sec where considering the clearance time critical gap and critical lag were 3.72 sec and 3.70 respectively showing a significant difference between these two methods.