In this study, data collected and published by the New York State Department of Motor Vehicles were used to examine the impact of hand-held cell phone ban laws enacted across all NY state counties. Crash rates were examined both pre- and post-law enactment. Results showed that after enacting the cell phone ban, 46 of the 62 NY state counties experienced lower fatal automobile crash rates, and in 10 counties these results were statistically significant. In addition, all of the counties experienced lower personal injury automobile crash rates after the ban was implemented. These results indicated that cell phone bans can decrease both crash rates and personal injury crash rates. Authors suggested that future research utilize time-series analysis and other analytic techniques to gauge whether laws prohibiting hand-held cell phone use while driving have a significant effect on the driving environment.
Nikolaev, A. G., Robbins, M. J., & Jacobson, S. H. (2010). Evaluating the impact of legislation prohibiting hand-held cell phone use while driving. Transportation Research Part A: Policy and Practice, 44(3), 182-193.