The Influence of Mixed Traffic on Congestion Level and Marginal Road Congestions

Urban traffic in most developing nations is heterogeneous in which the impact of different types of vehicles on road congestion would not probably similar. The impact, therefore, should be analyzed independently considering the dimension, speed, and proportion of each vehicle within the traffic stream. In theory, different types of vehicles influence less congestion can be utilized as a reason for traffic management measures. This study aims to develop an alternative method other than the use of the Indonesian Highway Capacity Manual (MKJI) for analyzing congestion level and marginal congestions. The proposed methods determine the passenger car equivalent (PCE), estimate the maximum capacity of a type of vehicle on a road link and predict congestion level and marginal congestions. Three road links selected as the case study are Jl. Mahendradatta, Jl. Buluh Indah and Jl. Cargo in Denpasar, Bali. This study found that the high proportion of small vehicles on the road such as motorcycles may also have a high influence on marginal road congestion. This study suggested that the maximum capacity and marginal congestion of each type of vehicle on the road link should initially be considered prior to perform traffic management policy such as prohibiting the entry of light and heavy vehicles while at the same time allowing motorcycles to have the access on certain road lanes.