Effects of enforcement intensity on alcohol impaired driving crashes

Abstract

Background Research measuring levels of enforcement has investigated whether increases in police activities (e.g., checkpoints, driving-while-intoxicated [DWI] special patrols) above some baseline level are associated with reduced crashes and fatalities. Little research, however, has attempted to quantitatively measure enforcement efforts and relate different enforcement levels to specific levels of the prevalence of alcohol-impaired driving. Objective The objective of this study was to investigate the effects of law-enforcement intensity in a sample of communities on the rate of crashes involving a drinking driver. We analyzed the influence of different enforcement strategies and measures: (1) specific deterrence -annual number of driving-under-the-influence (DUI) arrests per capita; (2) general deterrence -frequency of sobriety checkpoint operations; (3) highly visible traffic enforcement -annual number of traffic stops per capita; (4) enforcement presence - number of sworn officers per capita; and (5) overall traffic enforcement - the number of other traffic enforcement citations per capita (i.e., seat belt citations, speeding tickets, and other moving violations and warnings) in each community. Methods We took advantage of nationwide data on the local prevalence of impaired driving from the 2007 National Roadside Survey (NRS), measures of DUI enforcement activity provided by the police departments that participated in the 2007 NRS, and crashes from the General Estimates System (GES) in the same locations as the 2007 NRS. We analyzed the relationship between the intensity of enforcement and the prevalence of impaired driving crashes in 22 to 26 communities with complete data. Log-linear regressions were used throughout the study. Results A higher number of DUI arrests per 10,000 driving-aged population was associated with a lower ratio of drinking-driver crashes to non-drinking-driver crashes (p=0.035) when controlling for the percentage of legally intoxicated drivers on the roads surveyed in the community from the 2007 NRS. Results indicate that a 10% increase in the DUI arrest rate is associated with a 1% reduction in the drinking driver crash rate. Similar results were obtained for an increase in the number of sworn officers per 10,000 driving-age population. Discussion While a higher DUI arrest rate was associated with a lower drinking-driver crash rate, sobriety checkpoints did not have a significant relationship to drinking-driver crashes. This appeared to be due to the fact that only 3% of the on-the-road drivers were exposed to frequent sobriety checkpoints (only 1 of 36 police agencies where we received enforcement data conducted checkpoints weekly). This low-use strategy is symptomatic of the general decline in checkpoint use in the U.S. since the 1980s and 1990s when the greatest declines in alcohol-impaired-driving fatal crashes occurred. The overall findings in this study may help law enforcement agencies around the country adjust their traffic enforcement intensity in order to reduce im...

Impact of alcohol checks and social norm on driving under the influence of alcohol (DUI)

“…For example, Fell et al (2014) concluded from the data of the US National Roadside Survey that a 10% increase in the DUI arrest rate is associated with a 1% reduction in the drinking driver crash rate. In their meta-analysis on the effect on crashes of DUI checkpoints, Erke et al (2009) found that crashes involving alcohol are reduced by minimum 17% and that all crashes, independently of alcohol involvement, are reduced by about 10-15%.…”

Evaluating the Effectiveness of “No Refusal” Blood Draw Search Warrant Programs to Reduce Alcohol-Related Traffic Crashes in Central Texas

“…It is in local communities that these laws are enforced and reductions in alcohol-related traffic crashes save lives. Agencies have been using many strategies to enforce these laws, such as sobriety checkpoints, HVE, specialized DWI units, and most recently no refusal blood draw search warrant operations (Dula, Dwyer, and LeVerne 2007;Fell, Tippetts, and Levy 2008;Fell et al 2014;Wiliszowski and Jones 2003;Williams 2006). Enforcement of these particular laws comes at a cost, and must compete against other police responsibilities.…”

“…In 2012, this number reduced to 21 percent. Although this progress has been cited as remarkable and substantial, alcoholrelated traffic crashes still accounted for 10,322 fatalities in 2012 (Shults et al 2001;NHTSA 2012;Fell et al 2015).…”

Commentary on Yao et al. (2016): Enforcement uniquely predicts reductions in alcohol‐impaired crash fatalities

“…In a nationally representative study, Fell et al [3] found that a 10% increase in the DWI arrest rate per capita in a community was associated with a 1% decrease in alcohol-impaired driving crashes in that locality. Using a 11-year sample (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006) of state data from the Fatality Analysis Reporting System, Yao et al…”

“…In a nationally representative study, Fell et al [3] found that a 10% increase in the DWI arrest rate per capita in a community was associated with a 1% decrease in alcohol-impaired driving crashes in that locality. Using a 11-year sample (1996-2006) of state data from the Fatality Analysis Reporting System, Yao et al [4]-in a paper in this issue-studied states with increases and decreases in the percentage of alcohol-impaired fatal crashes during that 11-year period and found that states that had higher DWI arrest rates per capita had reductions in the percentage of fatal crashes involving an alcohol-impaired driver.…”