I. Introduction
Reducing traffic risks is one of the most important public safety concerns across the world. The global statistics by World Health Organization show that more than 1.35 million humans lost their lives every year due to the road traffic accidents [1]. Contrary to other calamities, it is well acknowledged that the traffic crashes are not chance events [2] and hence the majority of traffic crashes can be mitigated (avoided) via appropriate driving maneuvers at proper operation time [3], [4]. As shown in Figure 1, the subject vehicle (SV) changes lane and triggers the risk of potential conflict with an adjacent vehicle; if the SV steers to the right side at a proper short cushion time after detecting this risk scenario, the risk could be avoided. For this proactive crash mitigation purpose, some advanced driving assistance systems (DASs) that offer safety recommendations have been proposed in this driver-vehicle co-driving situation, and showed significant safety improvement [2], [5], [6].