Drugged driving in Louisiana: quantification of its impact on public health and implications for legislation, enforcement, and prosecution.

PDFTech ReportFHWA/LA.15/576Drugged driversPublic healthLegislationLaw enforcementTraffic safetyInterviewingZero toleranceData collectionDrunk drivingLouisianaLouisiana State University. Highway Safety Research GroupSchneider, HelmutPfetzer, EmilyLouisiana State University. Highway Safety Research GroupLouisiana. Department of Transportation and DevelopmentMississippi State University. National Center for Intermodal Transportation for Economic CompetitivenessUnited States. Federal Highway AdministrationUS Transportation CollectionDrugged driving, i.e., driving under the influence of drugs, is considered a rising public health issue in the US and the rest of the world, yet due to underreporting and limitations of existing data, not much is known about the frequency of drugged driving or how it affects public safety. While the federal government has encouraged states to enact zero-tolerance drugged driving laws, the lack of clarity surrounding the effects of drugs on driving abilities, as well a lack of empirical evidence about the efficacy of such laws, indicate more research is necessary. Using Louisiana as a case study, this report provides important insight into the state of knowledge about drugged driving, the limitations to current data collection practices, and how to proceed from here. There are two main goals: first, evaluate laws and policies about drugged driving and through a series of interviews with prosecutors, defense attorneys, police, and the public, identify obstacles to zero-tolerance legislation in Louisiana; and second, analyze the frequency of drugged driving in Louisiana and other states where data is publically available to identify ways to improve data collection. Analysis of data from the Louisiana State Crime Lab as well as other available sources provide a preliminary baseline estimate about the frequency and nature of drug-impaired driving in Louisiana. Findings indicate substantial disparities exist among parishes in terms of the number of drug-impaired driving arrests and the quality of evidence submitted for testing, which reflects a lack of standardized procedures and an uneven distribution of resources. This study compares the prior DWI arrests, speeding violations and crashes of drivers who tested positive for various drugs to all other drivers. While there are substantial limitations to the analysis, particularly in sample size and selection, the findings suggest the drivers arrested for drugged driving have higher rates of prior unsafe driving incidents than all other drivers. Survey interviews with the target populations reveal an overall lack of training, resources, and testing capacities in Louisiana, as well as a wide range of concerns about per se laws. This study contributes a clearer understanding of existing data limitations and challenges with which states must contend, and presents a series of recommendations for developing a comprehensive approach to dealing with drug-impaired driving in Louisiana and other states moving forward