| The use of mobile communication devices (MCDs) by drivers is a significant public health problem. Research suggests that MCD use plays a role in almost 400,000 traffic crashes each year, resulting in over 3,000 deaths (NHTSA, 2013). Drivers using an MCD are as much as four times more likely to crash as other motorists (Redelmeier & Tibshirani, 1997). Since 2001 forty-eight states have adopted one or more laws aimed at reducing the use of MCDs by drivers, many of which have been strengthened through subsequent amendments. Evaluations have yielded a mixed picture of their effectiveness (Braitman & McCartt, 2010; Highway Loss Data Institute, 2010; McCartt & Geary, 2004; McCartt, Hellinga, Strouse, & Farmer, 2010). Existing studies, however, have been limited by various design features. This study employs time-series methods to explore whether laws prohibiting use of MCDs by young drivers effectively reduce crash fatalities. The quasi-experimental design relies on an identification strategy that is common in empirical legal studies but has not yet been applied to laws regulating driver MCD use. The implementation of the identification strategy leverages the developing concept of legal epidemiology. Four state laws are ultimately evaluated. The primary analytic approach is difference-in-difference. In two of the four instances, there is some evidence suggesting a protective effect could be attributed to the law. However, this evidence was limited and differed in relation to specification choices. These findings cast doubt on some fifty state panel analyses that have suggested that laws are effectively decreasing MCD use and associated harms. |
