The Comfort of the Soft-Safety Driver Alerts: Measurements and Evaluation

Abstract

With the development of automated driving systems and V2I (vehicle-to-infrastructure) communications, soft-safety driver alerts can be implemented to supplement imminent driver alerts. This type of alert improves drivers’ situational awareness of emerging risks over a more extended period with more detailed incident information and longer response time. However, compared to the large number of studies focusing on imminent risks, there are insufficient studies on the evaluation and effectiveness of soft-safety alerts. This study proposed an innovative metric to assess the comfort and safety of soft-safety driver alerts by constructing an ideal speed profile and calculating the deviation between the actual and ideal profile. We select the highway end-of-queue event as the experiment scenario, which is a leading cause of fatal highway crashes. Human subjects’ experiments are conducted in the driving simulator to validate the proposed metrics. The results have proved that the proposed metrics have good potential to assess driving comfort objectively. We also found that soft-safety alerts tend to improve driving comfort. However, there is insufficient evidence to conclude statistically about the prototype soft-safety alerts implemented in the experiments.