An Evaluation of Arizona's July 1982 Drunk Driving Law: Effects on the City of Phoenix

In July 1982, Arizona implemented a Driving While Intoxicated (DWI) law which mandated severe penalties for DWI convictions. Interrupted time series analyses conducted using data from the city of Phoenix showed an initial estimated reduction of 7.44 vehicular fatalities per month when the law went into effect, which then slowly returned to baseline. In a switching replication, parallel results were found in San Diego for the effect of a similar January 1982 California law. No changes in fatalities corresponding to the implementation of the Arizona or California laws were found in the El Paso comparison series. Time series analyses of DWI‐related law enforcement activity in Phoenix showed no change associated with the implementation of the Arizona DWI law. Analyses of newspaper coverage in Phoenix suggested that another substantial decrease in fatalities occurred prior to the implementation of the law, coinciding with the beginning of intense media coverage of the DWI issue.