The impact of Michigan's text messaging restriction on motor vehicle crashes.
OBJECTIVE
The purpose of this study was to determine the effects of Michigan's universal text messaging restriction (effective July 2010) across different age groups of drivers and crash severities.


METHODS
Changes in monthly crash rates and crash trends per 10,000 licensed drivers aged 16, 17, 18, 19, 20-24, and 25-50 years were estimated using time series analysis for three levels of crash severity: (1) fatal/disabling injury; (2) nondisabling injury; and (3) possible injury/property damage only (PDO) crashes for the period 2005-2012. Analyses were adjusted for crash rates of drivers' aged 65-99 years, Michigan's unemployment rate, and gasoline prices.


RESULTS
After the introduction of the texting restriction, significant increases were observed in crash rates and monthly trends in fatal/disabling injury crashes and nondisabling injury crashes, and significant decreases in possible injury/PDO crashes. The magnitude of the effects where significant changes were observed was small.


CONCLUSIONS
The introduction of the texting restriction was not associated with a reduction in crash rates or trends in severe crash types. On the contrary, small increases in the most severe crash types (fatal/disabling and nondisabling injury) and small decreases in the least severe crash types (possible injury/PDO) were observed. These findings extend the literature on the effects of cell phone restrictions by examining the effects of the restriction on newly licensed adolescent drivers and adult drivers separately by crash severity.
Health Behavior Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland. Electronic address: johnathon.ehsani@nih.gov.
Johnathon P
JP
Ehsani
Young Driver Behavior and Injury Prevention Group, University of Michigan Transportation Research Institute, Ann Arbor, Michigan; Department of Health Education and Health Behavior, University of Michigan School of Public Health, Ann Arbor, Michigan.
C Raymond
CR
Bingham
Department of Statistics, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan.
Edward
E
Ionides
Center for Statistical Consultation and Research, University of Michigan, Ann Arbor, Michigan.
David
D
Childers
D000056:Accident Prevention / Q000379:methods*; D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data*; D000293:Adolescent; D000294:Adolescent Behavior; D000328:Adult; D000367:Age Factors; D000368:Aged; D001334:Automobile Driving / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D012309:Risk-Taking; D012919:Social Behavior; D060145:Text Messaging; D014947:Wounds and Injuries / Q000453:epidemiology* / Q000517:prevention & control
Adolescent driver; Distraction; Law; Motor vehicle crashes; Restriction; Texting