An investigation of speed variance effect on lane-changing for driving logic “cautious” on highways

High speed and large speed variation of vehicles on high-speed highways can increase the lane-changing risk. This study aims to evaluate and compare the effect of speed rate exceeding 5 to 30% above the speed limit on lane change frequency for driving logic “cautious” for significant traffic characteristics. Accordingly, VISSIM simulation was performed for a two-lane road section to measure the lane change frequency for single traffic and mixed traffic. The simulation data analysis found that the specified speed rate has a strong impact on lane changing. While the simulation plot results showed the positive relationships between speed rate and lane change frequency for most of the observed cases. However, for the few cases, the relationships were observed complex and non-significant mainly due to presence of Heavy Goods Vehicles (HGVs), and their high-speed rate. In addition, the study results noticed that the relationship between specified speed rate and lane change frequency depends upon other related traffic aspects such as traffic composition and road environment. Furthermore, the effect of speed rate on lane change frequency was observed high for freeway as compared to the rural expressway. The study framework could be a useful evaluation to highlight speed-related parameters which affect high on lane change frequency.