Dialing While Fishtailing: How Mobile Phones, Hands-Free Laws, and Driving Conditions Interact to Affect Traffic Fatalities

Most rich countries in the world and four US states require drivers talking on mobile phones to use hands-free devices. However, previous research has failed to arrive at a consensus on the effect of mobile phones on traffic accidents yet has concluded that the effect of hands-free and hand-held phones on accidents is similar. This paper uses state-level data from 1997-2005 on mobile phone ownership, traffic fatalities, and hands-free laws and finds that mobile phones contribute to traffic fatalities and hands-free laws appear to reduce fatalities. Specifically, mobile phone ownership results in a large and statistically significant increase in traffic fatalities in bad weather or wet road conditions, with no effect in good weather or dry road conditions.