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.