Driving simulator evaluation of an advance warning system for safe cyclist overtaking

Abstract

Among all crashes involving cyclists, a motorist approaching a cyclist on a shared lane from behind is particularly dangerous and likely to result in serious injuries and fatalities. Previous research has highlighted that inadequate lateral distance and high vehicle speed are among the main contributing factors of crashes involving cars overtaking cyclists. Since new technology innovations offer the potential to increase safety and mobility, a driving simulator study was conducted to evaluate the safety effects of an advanced driver-assistance system (ADAS) for cyclist overtaking. The ADAS was composed by a multimodal human-machine interface (HMI) using a multistage collision warning system, informing drivers well in advance about the potential danger so that an imminent cyclist collision can be avoided. Three warning priority phases were defined: (1) normal, (2) danger, and (3) avoidable accident. Both visual and acoustic signals were used to warn drivers. A combination of Lateral Clearance (LC) and Time-To-Danger (TTD) parameters was used as ADAS activation criterion. A general linear model showed a positive effect on the lateral clearance of the following variables: presence of the ADAS system, familiarity with the system, male gender, driving experience as car driver, and driving experience as cyclist. A negative effect was associated with the following variables: cyclist manoeuvring from the edge of the lane to the centre of the lane, cyclists riding in parallel, driver’s age, and self-reported aggressive driving. In conclusion, the drivers’ characteristics affected the LC and the ADAS significantly increased LC, indicating a positive safety effect on cyclist overtaking by cars. No significant effect on speed during overtaking was observed between the condition with or without ADAS, although it was observed that men drove on average faster than women.