Driver Understanding and Secondary Task Performance While Viewing Traffic Safety Messages on Dynamic Message Signs

Abstract

Many agencies use dynamic message signs to display behavioral traffic safety (BTS) messages (e.g., CLICK IT OR TICKET, DONT DRINK AND DRIVE). However, little guidance exists on how best to design and display such messages on those signs. In this paper, the results of a human factors laptop-based study are described, which examined how well drivers can read and interpret BTS messages while simultaneously attending to a secondary control task similar to how drivers must operate their vehicle while simultaneously reading road signs. The study results indicated that displaying BTS messages that include humor, wit, or pop culture references could have adverse consequences on driving behavior for motorists who are unable to correctly interpret the safety topic of those messages. The results also indicated that BTS messages should only address a single safety topic. The length of the BTS message should be kept to 16 words or fewer in low to moderate driver workload environments; in high driver workload environments, BTS messages should be limited to 11 words or fewer.