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Abstract
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The legalization and decriminalization of cannabis is occurring at a rapid pace for both medical and recreational use. In total, 31 states have legalized medical cannabis, along with Washington, D.C.; Guam, and Puerto Rico (NCSL, 2018). This legalization trend creates numerous potential public health challenges, but traffic safety may be particularly impacted. One critical concern is developing effective policy related to driving under the influence of cannabis (DUIC). Yet, only limited research exists on the effects of many impaired-driving policies as they specifically relate to cannabis, including the establishment of an illegal per se concentration of cannabis.
Currently, six states have per se laws with non-zero tolerance limits for cannabis. While intended as an effective legal countermeasure to cannabis-impaired driving, it is unclear how the establishment of non-zero tolerance per se limits affects the criminal justice system. This is largely due to the limitations of commonly used drugged-driving data sources, as well as the necessary linkage of these data to judicial outcomes, to appropriately assess these effects. Thus, the objective of this research is to assess the feasibility of studying the effect of non-zero-tolerance per se limits for cannabis on the legal system. The effects of these laws on judicial outcomes (e.g., convictions) are of particular interest.
The research herein was conducted using a literature review, as well as guided discussions with key state-level officials. The literature review focused on available data sources, data dictionaries, state legislation, and research on per se concentrations for cannabis and driving. Structured interviews were then conducted with representatives and stakeholders in each of the six states with non-zero tolerance per se limits for cannabis presence in drivers (Illinois, Montana, Nevada, Ohio, Pennsylvania, and Washington). The project sought to understand, for each state, what data is currently linked or would need to be linked in order to track outcomes of cases from the arrest through the disposition of the case, and what data processes would need to be enacted to link these data (i.e., whether records would need to be manually linked using case identifiers).
Each state examined in this study has its own unique policy, data systems, and potential for integration and so separate feasibility assessments are provided for each. In general, the ideal analytic approach requires data that specifically tracks all individuals arrested for per se violations throughout the entire legal process (including dropped or reduced charges and across all dispositions) from the time of arrest through the final disposition of the case. Furthermore, these data should differentiate cannabis-related offenses (specifically per se violations due to THC) from other types of impaired driving. This requires high-quality data across three general domains: law enforcement, toxicology, and judicial outcomes. The report discusses each in turn.
Keywords: Cannabis impaired driving |