An Experimental Field Test of Automotive Headway Maintenance/Collision Warning Visual Displays

Motor vehicle crashes resulting from one vehicle striking the rear-end of another are one of the most common types of crashes involving two or more vehicles. The National Safety Council reported (Accident Facts, 1992) that there were approximately 11.3 million motor vehicle crashes in 1991 of which 2.7 million were rear-end crashes (about 23.8% of the total). These crashes accounted for 33% of all collisions involving two or more vehicles. To address the rear-end crash problem, a color LCD display designed to indicate safe following distances was mounted in the instrument panel of an 1990 Olds Toronado Trofeo. The vehicle was also equipped with a laser range finder, forward view video camera, eye view camera, video multiplexer, and computer-controlled video cassette recorder. One hundred and eight drivers from three age groups participated in this field experiment in one of three display symbology conditions. Drivers were not explicitly instructed on how to use the headway displays. Data analyses indicated that (1) the drivers easily understood the displays, (2) those drivers who initially maintained unsafe headways increased their following distance when one of the display symbologies was used, (3) during events where changes in relative velocity (braking) took place, all three symbologies increased the overall headways, and (4) drivers preferred and understood, even better, displays that included graded headway/warning information.