Autonomous negotiation of freeway traffic

This paper presents a new approach for autonomously negotiating freeway traffic. It is based on the concept of Velocity Obstacle (VO) which maps the set of vehicle's velocities that would result in a collision with the other moving vehicles. The Velocity Obstacle is computed by measuring the relative velocities and positions of the neighboring vehicles. The vehicle then negotiates through the moving traffic by selecting velocities that are out of that set, but are directed towards the intermediate goal, which may be an exit ramp or another lane. The computation of the VO and the feasible velocity is repeated at regular time intervals, to account for the time evolution of the freeway traffic. This representation can be used to automatically plan the vehicle's motion, or to advise the driver of potential unsafe maneuvers. For automatic planning, we developed heuristics that select the safe velocity based on the location of the goal and the acceptable risk level of the maneuvering vehicle. For advisory purposes, we developed a graphic representation of the VO which clearly shows the unsafe velocities to be avoided at all times. Attempting to drive at an unsafe velocity may sound an alarm and suggest a corrective maneuver. This representation is computationally efficient, and is applicable for on-line planning and warning. The method is demonstrated in simulations for planning the trajectory of an automated vehicle in an Intelligent vehicle Highway System (IVHS) scenario.