Lack of Uniformity in State Drugged Driving Laws
"Overall, the State-by-State analysis indicates there is a lack of uniformity or consistency in the way the States approach drugged drivers. Having no separate offense for driving under the influence of drugs makes it difficult to distinguish between DUID and DWI-alcohol arrests and dispositions. A recent attempt to investigate the effectiveness of drug per se laws was unable to draw conclusions due to the paucity of objective data and the inability of State data systems to distinguish between DUID and DWI-alcohol arrests and convictions (Lacey, Brainard, & Snitow, under review). In addition, in cases where a driver shows evidence of impairment by multiple substances, the lack of difference in sanctions between drug-impaired and alcohol-impaired driving provides little incentive for criminal justice officials to pursue a drug-impaired driving charge in addition to an alcohol offense."
Walsh, J. Michael, "A State-by-State Analysis of Laws Dealing With Driving Under the Influence of Drugs," The Walsh Group (Bethesda, MD: National Highway Traffic Safety Administration, December 2009), p. 6.