L Capacity Evaluation of AT-Grade Intersection

The urban traffic congestion has become a global phenomenon. Rapid urbanization and industrialization have caused an unprecedented revolution in growth of vehicles all over the world. Environmental pollution is one of the problems faced by humanity these days. Due to fast growing vehicular traffic, cities become congested and road links, intersection become saturated, busy and supply service is above its capacity. Therefore, it requires effective controls to regulate the traffic and optimize delay and congestion of the traffic at the intersection. Space sharing intersection e. g rotaries and pretimed signals are widely used to control the intersections. Space sharing intersection are intended to give equal priority and permit continuous movement of all intersecting vehicle flows. For higher traffic volumes, space sharing intersections such as rotary is not preferable due to increase in congestion and overall intersection delay and conflicts. In pretimed signal, green times for the phases remain constant for the particular period of the day, although demand fluctuates during that period. This problem can be eliminated by providing over bridge at rotary intersection. This study presents literature review on At-grade Intersection and Grade separated Intersection and literature on case study. Shivranjani signalized intersection on 132ft ring road is selected as a case study intersection. The flow rate, saturation flow rate and its adjustment factors, capacity, volume to capacity ratio, delay for lane group, approaches and intersection as whole and delay comparison with level of service were calculated as described in highway Capacity Manual 2000. Past study proves that shivranjani at-grade intersection was required to be converted to grade separated intersection to reduce congestion and delay.