Fig. 1

Map of states included in 2008–2013 NOPUS survey. Whilst the survey is nationally representative, not all states were sampled. States shaded in white were not sampled; Alaska and Hawaii were also not sampled (not shown). States in any shade of grey were sampled. States shaded in dark grey had a universal hand-held cell phone use while driving ban implemented before or during the survey period. Illinois and New Hampshire had universal hand-held bans, which became effective after the study period (January 2014 and July 2015, respectively)