Prospective Evaluation of the Collision Severity L7e Vehicles Considering a Collision Mitigation System

Abstract

SEV (small electric vehicle) is one of the future solutions for urban mobility, since these cars show a small environmental footprint due to their lightweight design for optimizing the range. Due to the low number of SEVs in real accidents it is difficult to judge the collision severity of these vehicles, especially if such vehicles are equipped with ADAS (Advanced Driver Assistance Systems) in order to avoid accidents or mitigate injury severity.The objective of this study is to analyze the collision severity of SEVs in real accidents to assess the injury severity of the occupants. Further the effectiveness of a collision mitigation system (CMS) that aims to reduce impact speeds or, if possible, avoid collisions of passenger cars is evaluated.The method used in this study refers to the virtual pre-crash simulation. In a first simulation (called the baseline simulation) the original vehicles were successively replaced by an L7e so that collisions between original cars and L7e cars are considered. In a second simulation (system simulation) it was assumed that the L7e vehicles are virtually equipped with a CMS. Certain characteristics of the CMS such as sensor range or opening angle and various response strategies were varied. The response strategies under investigation are:a)warning to the driver at 2.6 s TTC (time to collision) and fully braking after 0.8 s reaction time,b)braking with 50% brake force at 1.6 s TTC and fully braking at 0.8 s TTC,c)braking with 50% brake force at 1.6 s TTC and finallyd)fully braking at 0.8 s TTC.Occupants of L7e vehicles generally have a higher risk to suffer MAIS3+ injury than in M1 vehicles. The analysis showed a reduction of the risk to suffer a MAIS3+ injury up to 65% when involved in an accident situation in an L7e vehicle for CMS with sensor system 1 and up to 87% with sensor system 2.