Simulation Approach for Analysis of Signalized Intersection Capacity Under the Influence of Access Point: A Case Study

The interaction between surrounding activities and regular traffic at signalized intersections leads to a reduction in their performance. Such activities include flow from an access point, on-street parking, etc. The effect of access traffic near signalized intersections is not much explored. Manuals like HCM (2010) and Indo HCM (2017) do not address the potential change in capacity due to this factor. This research is an assessment of the influence of access flow on the capacity of nearby signalized intersections under mixed traffic environment. The videographic data from the field is collected during peak hours. Indo HCM method is followed to analyze the capacity at signalized intersections. The outcome of this study shows there is a significant effect on the capacity of the signalized intersection if there is an access point in proximity. The maximum capacity reduction observed was in the range of 19 to 24%. A microsimulation model was developed using VISSIM to study the effect of varying access flow (zero to 285 PCU/hour) and distance of access point from stop line (10 m to 120 m) on the capacity of the intersection. It was observed that an increase in access flow causes more reduction in capacity. Position of access point also plays a crucial role as it is observed that beyond 100 m from the stop line of the approach considered, the access flow has less effect on the capacity and beyond 120 m, the effect diminishes. Hence while designing a signalized intersection, planners should ensure there is no access point within 100 m of the intersection. The result of this study will be useful for planners and academicians for capacity evaluation of signalized intersections.