Estimation of Drivers’ Critical Gap Acceptance and Follow-up Time at Four – Legged Unsignalized Intersection
Biliyamin Adeoye Ibitoye, Rasheed AbdulWahab, and Sikirat Damilola Mustapha
Department of Civil & Environmental Engineering, College of Engineering &Technology
Kwara State University, Malete, P. M. B 1530, Ilorin, Kwara State, Nigeria
Email: biliyamin.ibitoye@kwasu.edu.ng
ABSTRACT
Intersections which are meant to facilitate the convenience, ease, and comfort of people traversing them appear to be most hazardous locations on roadway systems. This study aims at determining the driver’s critical gap at Shao expressway intersection. The morning and evening peak traffic flow was captured using a video camera for seven days and then analyzed by playing back the video on daily basis. The camera was placed at a suitable height in order to cover all area of the intersection. The traffic count data show the most prevalent operations at the minor indicating frequent peak hour flows along Ilorin – Malete due to location of Kwara State University at Malete. The resulted critical gap which is the minimum gap that all drivers in the minor stream are assumed to accept at all similar location is 2.9sec and this is lower than 6sec recommended by the HCM (1995).This implies that most drivers using Shao intersection are in a hurry to cross the major road, thereby resulting into potential conflicts or serious accident. Thus, there is need to improve the geometrical features of the intersection as well as to introduce appropriate control mechanism at the intersection.Keywords: gap acceptance, critical gap, unsignalized intersection, follow up time
