Analysis of effects of a motorcycle pre-crash braking system using in-depth crash data and drive-through data: a case study

Motorcyclist safety will remain an important issue for society because motorcycle usage is expected to increase in the coming years, especially in cities affected by traffic congestion problems. Recent studies have reported on the progress of Pre-Crash Braking (PCB) systems on motorcycles, showing that higher automatic decelerations now seem more viable. In particular, the experiments conducted by Merkel et al. [1] suggested that automatic decelerations of up to 5 m/s2 may be sustained by normal riders, whereas previous studies had assumed a more conservative value of 3 m/s2. A consequence of the higher deceleration produced by PCB is a greater reduction in impact speed, which potentially leads to larger benefits in terms of injury mitigation. Another way to increase the effects of PCB is to deploy the system earlier than the moment when the collision becomes inevitable [2], an approach that is in accordance with the opinions of expert riders provided in a previous field study [3]. Here, the authors define PCB ‘late intervention’ as a deployment produced when a collision between the host powered two-wheeler (PTW) and opponent car cannot be avoided with any manoeuvres involving accelerations of up to 1 g. When assuming a max. acceleration of 0.7 g for the avoidance manoeuvres, the deployment of PCB would occur earlier in time. This triggering condition is defined as ‘early intervention’. This paper presents the analysis of a case study aiming to assess the effects of: (i) a modified triggering threshold; and (ii) a modified automatic deceleration for a PCB system.