Accident; analysis and prevention
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Forward collision warning (FCW) and autonomous emergency braking (AEB) systems are increasingly available and prevent or mitigate collisions by alerting the driver or autonomously braking the vehicle. Threat-assessment and decision-making algorithms for FCW and AEB aim to find the best compromise for safety by intervening at the "right" time: neither too early, potentially upsetting the driver, nor too late, possibly missing opportunities to avoid the collision. Today, the extent to which activation times for FCW and AEB should depend on factors such as pedestrian speed and lane width is unknown. ⋯ Fractional factorial design effectively compared the influence of seven factors on driver behaviour within a single experiment; however, this design did not allow in-depth data analysis. In the future, OpenDS might become a standard platform, enabling crowdsourcing and favouring repeatability across studies in traffic safety. Finally, this study advises future design and evaluation procedures (e.g. new car assessment programs) for FCW and AEB by highlighting which factors deserve further investigation and which ones do not.
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For pedestrians, the risk of dying in a traffic accident is highest on rural roads, which are often characterized by a lack of sidewalks and high traffic speed. In fact, hitting the pedestrian during an overtaking attempt is a common crash scenario. To develop active safety systems that avoid such crashes, it is necessary to understand and model driver behavior during the overtaking maneuvers, so that system interventions are acceptable because they happen outside drivers' comfort zone. ⋯ This study is the first to analyze driver behavior when overtaking pedestrians, based on field test and naturalistic driving data. Results suggest that pedestrian safety is particularly endangered in situations when the pedestrian is walking opposite to traffic, close to the lane, and when oncoming traffic is present. The Bayesian regression models from this study can be used in active safety systems to model drivers' comfort in overtaking maneuvers.
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Crosswalk markings are a type of facility installed at the vehicle-pedestrian interaction locations and the function is to warn drivers to watch out for pedestrians crossing the street and improve safety for pedestrians. In Beijing, a type of new-designed crosswalk markings in China (NCMC) was installed. However, evaluating the effectiveness of this type of crosswalk markings was not conducted. ⋯ The evaluation result showed that, for intersections with high or low pedestrian flow, the comprehensive effectiveness and influences on drivers' driving behaviors with presence of NCMC were better than those with presence of SCMC, no matter where vehicle-pedestrian interactions occurred. For intersections with no pedestrians, the comprehensive effectiveness and influences on drivers' driving behaviors with presence of NCMC were worse than those with presence of SCMC, no matter where vehicle-pedestrian interaction occurred. These results may provide references for facility installing and future development of standards.