Drug Per Se Laws: A Review of Their Use in States

This report summarizes a study of the implementation of drug per se laws in 15 States. These laws generally make it an impaired-driving offense to drive with a measurable amount of certain drugs in one’s system. The specific prohibited drugs vary by State. The laws are generally integrated into the States’ overall impaired-driving statute. Though all 15 States were studied to some degree, deeper study of the process was conducted in 6 States. This involved discussions with government officials and law enforcement officers, and a series of structured discussions with prosecutors. This study was not an impact evaluation of drug per se laws on crashes, but rather an attempt to gain an understanding of how the drug per se laws are implemented and perceptions about the law of those charged with implementing the law. It was initially intended that the study would also assess the effect of passing driving under the influence of drugs (DUID) per se laws on the volume of DUID arrests and on conviction patterns, but data to directly address those issues were not available. A general consensus among law enforcement officers, whom the authors held discussions with, was the adoption of drug per se laws did not necessarily make enforcement easier, but did have a positive effect on prosecution. This general perception was shared by prosecutors whom the authors interviewed. Because the drug per se laws have typically been adopted as a component of States’ impaired-driving statutes, one difficulty of this study was obtaining accurate data on volume of arrests and conviction rates for the DUID component of the impaired-driving law. Recommendations include developing a procedure where impaired-driving citations indicate drugs, alcohol, or both, but also adopting procedures to ensure information is integrated into computerized data systems of both law enforcement agencies and courts.