Calculating the Brake-Application Time of AEB System by Considering Maximum Deceleration Rate during a Primary Accident in Penang's Urban Road

Abstract

An experimental study of the brake-application time of Autonomous Emergency Braking (AEB) system considering the primary accident in an urban area was proposed. Since the functionality of the brake-application time is varied between manufacturers and models, the brake-application time of AEB system must be verified based on driving behaviour in Malaysia. A primary accident was simulated to acquire vehicle deceleration rate in real condition by driving an ego vehicle at a different set of vehicle speeds. The study is focussed on the urban roads in the north region of West Malaysia, i.e. Penang. As a benchmark in this study, the brake-application time (2.6 s) introduced by Mercedes-Benz in the PRE-SAFE® Brakes technology was referred. A new braking permission time was proposed by calculating a minimum deceleration distance and Time-to-Collison (TTC) confirmation time required to brake based on maximum deceleration when a primary accident was simulated. It was found that the brake-application time recommended for the AEB system, specifically AEB City conveys the real driving condition of Penang when a primary accident happens in the urban area. To have a smooth braking and an optimum braking performance during a primary accident, the Forward Collision Warning (FCW) should be activated at TTC ≤ 4.6 s. The partial braking (PB) should be activated automatically when the TTC is approximately 2.9 s. While the automated full braking (FB) phase should begin when the TTC reaches 1.1 s.