Are Drivers Who Use Cell Phones Inherently Less Safe?

James E. Prieger and Robert Hahn
Robert Hahn
Robert Hahn Director of Economics - Smith School of Enterprise and the Environment at the University of Oxford, Former Brookings Expert

May 1, 2007

EXECUTIVE SUMMARY  Mobile phone usage while driving is increasing throughout the world. In this paper, we use survey data from 7,268 U.S. drivers to estimate the relationship between mobile phone use while driving and accidents. We hypothesize that drivers who use mobile phones while driving may be more likely to get into accidents than drivers who do not, even when they are not using the phone.

We find evidence for the endogeneity of mobile phone and hands-free device usage, and our analysis suggests that individuals who are more likely to use hands-free devices are more careful drivers even without them. Once we correct for the endogeneity of usage, our models predict no statistically significant increase in accidents from mobile phone usage, whether hand-held or handsfree. Our results call into question previous cost-benefit analyses of bans on mobile phone usage while driving, which typically assume that such bans will have a salutary effect.