Critical headway estimation under uncertainty and non-ideal communication conditions

This article proposes a safety check extension to Adaptive Cruise Control systems where the critical headway time is estimated in real-time. This critical headway time estimate enables automated reaction to crisis circumstances such as when a preceding vehicle performs an emergency brake. We discuss a method for critical headway approximation that can handle uncertainty in vehicle state, vehicle behaviour and communication in real-time. We then introduce an extension to the method that can handle effects of loss of messages and effects of event-based messaging the loss of messages. We simulate non-ideal communication and analyse how the critical headway time depends on the communication frequency.