Impacts of communication delays on wireless-based automated vehicle control systems

While existing adaptive cruise control systems and collision warning systems are designed for comfort and safety benefits, both applications are associated with potential problems related to their reliance on radar sensors in detecting nearby vehicles and objects. The most concerned problem is that only neighboring vehicles can be detected, yielding a very limited view of surrounding traffic conditions. A remedy for this limitation is to feed individual vehicles with traffic data of other vehicles via vehicle-to-vehicle communication. Although additional information may provide opportunities for performance improvements, wireless communication delay must still be considered for its potential impact on the safety of vehicle occupants.; This study primarily focused on the development of vehicle control algorithms robust to information delays. To this end, a current assessment was conducted on the state-of-the-art in vehicle-to-vehicle communication and driver assistance systems and the existing research on the impacts of wireless communication delay. A microscopic traffic simulation model was then developed to enable the simulation of Intelligent Transportation Systems (ITS) applications using onboard vehicle sensors or wireless communications. This simulation model has been used to assist with the development of a vehicle control algorithm making vehicle acceleration/deceleration decisions based on delayed information from multiple downstream vehicles.; Upon completion of the vehicle control algorithms, various evaluations were conduct to assess its behavior under various levels of communication delays, alternative multi-vehicle anticipative control environments, and various proportion of vehicles equipped with the proposed control algorithms within a stream of vehicles otherwise controlled by ordinary drivers. These evaluations were carried out using the traffic simulation model that has been developed and looked more specifically at vehicle responses within three car-following scenarios: single-file platoon accelerating from standstill, vehicles responding to a slowdown by the platoon's lead vehicle, and vehicle responding to the sudden immobilization of the platoon's lead vehicle.; The simulation results clearly demonstrate that information delay has impacts on vehicle control algorithm and that this parameter should not be overlooked when vehicle safety and stability could be affected. Two evaluation scenarios have shown significant influence from the level of information delay considered. The simulation results further indicate the ability of the proposed algorithms to effectively reduce the sensitivity of vehicle control decisions to information delay. In particular, it is demonstrated that multi-anticipative vehicle control algorithms offer significant safety benefit, particularly in harsh situations. The presence of manually controlled vehicles within a stream of automated vehicles showed a clear negative impact on the performance of the vehicle control algorithm. Although manually controlled vehicles are not being fully considered in the decision making process, such evaluation results may still help determine the degree to which additional benefits may be obtained by any increase in the market penetration of the proposed algorithm.