Cell Phone Conversation and Relative Crash Risk

Abstract

Two pioneering studies that examined cell phone billing records of people who had been in automobile crashes estimated that cell phone “use” while driving elevated crash risk by a factor of four relative to driving without cell phone use, a substantial increase. Cell phone “use” in these pioneering studies refers solely to cell phone conversation, because billing records contain no information about the visual-manual aspects of cell phone use. Recent research suggests that these pioneering studies overestimated the relative risk of cell phone conversation by a factor of seven due to two major biases. After adjustment for these biases, cell phone conversation does not increase crash risk beyond that of driving without a cell phone conversation, and may, in fact, reduce crash risk. The main reasons are driver self-regulation and reduced drowsiness, which fully compensate for the slight delays in brake response times caused by cell phone conversation.