Collision analysis of vehicle following operations in automated highway systems

In Automated Highway Systems (AHS), vehicles are automated to maintain a desired speed and safe distance from the preceding vehicles. The vehicles also maintain their positions within a lane or on their designated path. One of the safety concerns for such systems is the consequences in failure or malfunctioning events when collisions occur. The work presented by this paper investigates the responses of vehicles in collisions, especially when they are closely spaced. This study uses a two-dimensional simulation software which allows longitudinal and lateral movements as well as the yaw motion of vehicles. The simulation model calculates impact forces in collisions and estimates the resulting vehicle damage. The study is an extension of several previous studies on this subject which have emphasized on the one-dimensional dynamics of vehicle impacts. The addition of vehicle motions in other axes provides a meaningful representation of real-world crashes. Collision situations, representing failure or malfunctioning events, are simulated. The subsequent post-impact vehicle trajectories are then analyzed. By varying parameters in simulation cases, one can evaluate the potential effects of such variables in vehicle-following operations. Through a systematic approach, correlation between the collision consequences and the operating variables in AHS can be established. The results of this analysis may also provide valuable inputs to the design of control systems. Proper emergency handling strategies and control laws may be developed to mitigate collision consequences. These studies are essential in the understanding and improvement of safety design in AHS.