The Development of Lane Utilization and Speed-Density Model for Multilane Highway: A Case Study in Islamabad Pakistan

Abstract

Islamabad Expressway is a multilane urban road that provides access between Islamabad the Capital of Pakistan and Rawalpindi. The traffic composition on Islamabad Expressway is varied with a high proportion of cars and other vehicles like buses, trucks, and bikes. Different factors affect lane usage of a road section such as speed of vehicles, rate of traffic flow, and composition of vehicles. Limited study has been conducted on the assessment of speed-density model and lane utilization patterns for various vehicle classifications on multi-lane highways. In this research endeavor, an eight-hour video data set was recorded from the Islamabad Expressway utilizing a mobile camera during both peak and off-peak hours to encompass a diverse range of traffic scenarios on the road. A model was established to estimate the correlation between speed and density and a corresponding mathematical equation was derived. Four vehicular categories are considered for studying lane utilization behavior. The lane utilization behavior was modeled using the lane utilization factor for all four lanes and structural equations were developed for lane utilization factors for all four lanes using SPSS software. The results of our study will help future researchers to check the behavior of speed with density on the Islamabad expressway and compare traffic characteristics with other roads in Islamabad and to check the behavior of lane utilization and lane discipline. The results of our study are also helpful for road development authorities to design the lane following their usage. The study outcomes can contribute to the development of micro-level traffic simulation models.