Environmental and traffic assessment of adjusting Triple Highway Capacity Manual (HCM) factors at signalized intersections

Abstract

Kuwait traffic networks has started to develop in the early 60’s. Since it is crucial to determine the parameters that present the local conditions in Kuwait, this study was developed to modify the passenger car equivalent (PCE) values at different signalized intersections in Kuwait and obtain the heavy-vehicle adjustment factor. The headway ratio method was utilized to determine the PCE values for different kinds of vehicles. 1. The PCE values were 1.14, 1.11, 1.26, 1.68 and 1.48 for sport utility vehicles (SUV), pickups, minibuses, trucks, and buses respectively. 2.The heavy vehicle adjustment factor was 0.891. Synchro simulation software was utilized to build different scenarios for improving an existing intersection and compare the network performance for each scenario. Two scenarios were chosen to be the best which are having five lanes with 2.4 m width for the first scenario and 2.7 m width for the second one. 3. Based on Synchro results, fuel consumption and pollutant emissions parameters were used to estimate the cost difference in the two best scenarios, and it was 10.71 and 13.23 Kuwaiti dinar (KD), respectively. Also, the percentage reduction of the emissions were 15.5% and 19.19%, respectively. The impact of adding an extra lane was noticed to be better compared with increasing the lane widths in a significant way. Additionally, it is a must to localize the parameters to represent the local conditions in Kuwait. The heavy-vehicle adjustment factor has an essential effect on the network performance which indicates that the PCE values should be determined accurately.