Investigating the Relation between Level of Service and Volume-to-Capacity ratio at Signalized Intersections under Heterogeneous Traffic Condition

摘要

Among the various performance measures for assessing the operational condition of signalized intersection, both volume-to-capacity (v/c) ratio and control delay have gained importance universally. Even though delay is used as the service measure for arriving at the level of service (LOS) of signalized intersection, the practitioners usev/cratio as the prime indicator of intersection performance. This study aims at understanding the significance of using thev/cratio as an indicator of signalized intersection performance under Indian context. Previous studies and various highway capacity manuals have proposed a one-to-one relationship between delay andv/cratio. The relationship has been revisited to find out whether there is a one-to-one correspondence. Further, an attempt was made to investigate the relationship between level of service and thev/cratio at signalized intersection under heterogeneous traffic condition. The delay model proposed in the Indian Highway Capacity Manual (Indo-HCM) has been used for this. The results show that the delay distribution under different degrees of saturation are overlapping and it is difficult to arrive atv/cthresholds for each LOS category. i.e. there is no one-to-one correspondence betweenv/cratio and delay values. Based on the study results, some approximate thresholds ofv/cratios are proposed for LOS of signalized intersections under heterogeneous traffic condition.