Automotive collision avoidance system field operational test : warning cue implementation summary report.

This report documents the human factors work conducted from January to June 2001 to design and evaluate the driver-vehicle-interface (DVI) for the Automotive Collision Avoidance System Field Operational Test (ACAS FOT) program. The objective was to develop an interface that most effectively supports the human interaction with the Forward Collision Warning (FCW) and Adaptive Cruise Control (ACC) systems. The DVI visual display sequences were developed for projection onto a full-color head-up display (HUD). Unlike previous generation HUDs, the new design was reconfigurable, facilitating the display of multiple-stage multicolor icon sequences for communicating the FCW alert level. Whereas the CAMP (1999) FCW project had focused only on single-stage monochromatic alerts largely because of implementation practicalities, the flexibility of the new HUD platform allowed a deeper analysis of how the output of the forward collision warning algorithm should be displayed to the driver. Two experiments were designed to examine the effectiveness of a range of multiple-stage alert candidates compared with a single-stage alert. Experiment 1 (Performance evaluation) employed a driving simulator to evaluate the impact of the display candidates on the brake reaction time (BRT) of drivers to an unexpected lead-vehicle braking event. The data revealed that some multiple-stage candidates facilitated earlier BRTs compared with the single-stage alert. This was evident of the display sequences that exhibited a looming quality (expanding visual image representing imminent collision), but not observed for the displays that did not. Experiment 2 (Preference evaluation) was designed to investigate the driver acceptance of the display candidates. Twelve drivers experienced four display candidates in the driving simulator and answered questions regarding their preferences and the annoyance induced by the displays. Although only twelve participants took part in the experiment, age appeared to have an influence on driver's responses. Whereas younger drivers appeared to prefer simpler (fewer stage) displays, middle and older drivers appeared to prefer more complex displays. Based on the combined data from the two experiments, the looming display was selected as the most promising candidate. (Author/publisher)