The European Union requires an Automatic Emergency Braking System (AEBS) for all new heavy trucks (N3) since 2015. In case of an anticipated rear-end collision, the AEBS in accordance with EU regulation 347 – 2012 has to provide an adequate two-fold warning cascade and a subsequent emergency braking. After becoming a mandatory system, a strong increase of market penetration of AEBS has been established. However, first analyses in 2017 on German highways showed only minor impact of AEBS in the field [Petersen, E., “Wirksamkeit von Sicherheitssystemen im Straßengüterverkehr”, Zukunftskongress Nutzfahrzeuge, Berlin, 08. Nov. 2017]. Identified reasons for the minor impact are, amongst others, overruling of the AEBS by braking / accelerating, a probable system deactivation by the driver, and limited implications of an EU conform AEBS. Concerning the requirements, the EU conform system demands in its current level (effective November 2018), for instance, a deceleration of 20 km/h during an emergency braking on a highway approaching with 80 km/h a standing opponent at the end of a traffic jam– the collision may still occur with up to 60 km/h. Being aware of the limitations of AEBS requirements, BOSCH established top level requirements for a high-performance AEBS assumed to not only mitigate but to prevent most rear-end collisions of trucks.
The present study evaluates the benefit of Automatic Emergency Braking Systems exemplarily for German roads. It comprises of a thorough analysis of rear-end collisions involving N3-trucks, followed by stochastic simulations of a truck assumed to be equipped with either of the systems: the current EU-conform AEBS or a generic high- performance Automatic Emergency Braking System. In the first part of the study, the German in-depth accident study (GIDAS) was used to identify a potential field of effect for AEBS. In the second part, a simulation frame work specifically designed for the stochastic approach was established. It includes a sensor system, various road conditions from on-spot measured data and a simplified truck driver model accounting for driver reaction times and the specific kind of driver reaction.
About 2 300 N3-truck rear-end collisions with casualties per year in Germany can be positively influenced by an AEBS (field of effect for truck AEBS). In the second part of the study, after 2.5 mio stochastic simulations, avoidance potentials of at least 7% for the EU-conform minimum system and up to 84% for the high-performance AEBS were identified (assuming full AEBS penetration in N3 vehicles). These avoidance potentials could scale up to 1 900 collisions with casualties in Germany per year, if each truck would be equipped with the high-performance AEBS. For the remaining accidents the collision velocity would be significantly reduced, too.
In summary, this study reveals that an AEBS applied to and accounting for real-world accident situations can increase the effectivity of an Automatic Emergency Braking System preventing rear-end collisions of trucks