Driving Simulator Evaluation of Driver Performance During Hands-Free Cell Phone Operation in a Work Zone: Driving Without a Clue.

Crashes continue to be a problem in work zones. Analyses have indicated that rear-end and sideswipe crashes are the most frequent. Investigators have hypothesized that distractions are often the cause of both types of crashes. These distractions will only increase as more drivers attend to other tasks, such as cell phone conversations. In order to address this issue, virtual worlds that reflect various work zone geometries were developed for an advanced driving simulator. These worlds contained 32 virtual work zones, and 38 drivers navigated through these worlds. On one portion of a trip, the drivers were asked to respond to a series of short sentences, which mimicked a hands-free cell phone conversation; on the other portion of the trip, no sentences were read to the drivers. A lead vehicle ahead of the participant driver braked occasionally in the work zone activity area. Braking scenarios involved either the lead vehicle stopping after an advanced clue that traffic ahead was going to stop or the lead vehicle stopping for no apparent reason, most often after passing a roadside obstacle (potential distracter). Drivers not engaged in a cell phone task were able to reduce their speed earlier in response to a slowing lead vehicle than were drivers engaged in the cell phone task. Drivers on the cell phone were also more likely to brake hard and less likely to make a mirror glance when changing lanes. The results strongly suggest that cell phone use reduces driver awareness and will increase the two major types of crashes in work zone activity areas, which are rear end and sideswipe collisions.