Evaluation of Forward Collision Warning System Visual Alert Candidates and SAE J2400

Forward Collision Warning (FCW) systems are intended to alert drivers when they may be at risk of a rear-end crash with a vehicle directly ahead unless they take immediate action. A forward collision visual alert (FCVA) is recommended as part of a multi-modality FCW system crash alert approach also including auditory and/or haptic crash alert components. SAE J2400 recommends that a conventional dashboard location shall not be used for the FCVA, since such an alert may distract the driver from the crash threat ahead (instead of helping the driver visually orient toward the crash threat). This research examined the merit of this recommendation by examining the effectiveness of instrument panel, head-up display, and (vehicle-centerline) top-of-dashboard FCVA candidates. In this static on-road study, 49 subjects (20–70 years old) made rapid judgments on the presence and nature of scene changes over two successive forward scene exposures controlled by a visual occlusion window. Scenes consisted of full-scale “pop up” vehicle and pedestrian targets. During the occluded period between scene exposures, drivers performed an “eyes-off-road” visual distraction task (located at either a center console or left side mirror location) until the window opened or they received a FCVA (which signaled them to abort the distraction task and prepare for an imminent window opening). Additional trials were conducted involving only alert detection. Results for the change detection and alert detection trials indicated that the overall time savings benefit for the larger HUD and top-of-dashboard alert types examined relative to the instrument panel alert type was 120 and 160 ms, respectively. A follow-on eye movement time-course analysis suggests that the benefits of these alert types have different underlying mechanisms. Overall, these results support the SAE J2400 recommendation advising against the use of instrument panel FCVAs and should be used to further refine FCVA-related SAE J2400 recommendations.