An analytical model for a three lane unidirectional freeway has revealed that traffic distribution in an individual lane can be more accurately expressed by total traffic flow, heavy vehicle composition and average speed, while the model for two lane unidirectional freeway revealed that traffic distribution can be best expressed by total traffic flow. Further, statistical tests were used to provide some insight into how changes in directional flow, location, geometry features, amount of heavy vehicle and light condition might affect the pattern of traffic distribution. Moreover, the amount of lane-changing highly affects the traffic distribution, and controlling vehicle movement from lower utilised lanes will improve its lane traffic flow. Further, from lane-by-lane speed/density/flow and lane utilisation analyses, two freeway capacity improvement measures are suggested, such as adding a short passing lane to the lower utilised lane and increasing the width of the lower utilised lane. (A)
Abstract