Police have few options when marijuana impairment is suspected

Arizona residents voted narrowly in November 2016 to defeat a ballot measure that would have legalized recreational marijuana use in the state. When the final votes were counted, law enforcement officers across the state may have let out a sigh of relief. Some fear that legal recreational marijuana would lead to a surge in the number of impaired drivers on Arizona roads, and law enforcement has little in the way of effective tools to counter this perceived threat.

Credible science has linked elevated blood alcohol levels with diminished driving skills. However, high amounts of THC, the compound in cannabis responsible for a euphoric high, in a driver’s bloodstream could mean very little. Police have generally relied on standard field sobriety tests to determine whether or not motorists are impaired by marijuana.

However, the reliability of field sobriety testing in marijuana cases has been questioned. These tests have been rigorously evaluated and found to be highly effective at identifying alcohol impairments, but marijuana affects drivers in different ways. Software has been developed that may be better able to identify reduced reaction times and problems handling distractions. However, it could take years for any new testing protocol to be assessed sufficiently to withstand legal scrutiny.

The lack of any reliable way of identifying marijuana impairment is often portrayed as a challenge for law enforcement and prosecutors. Prosecutors must prove drunk driving charges beyond reasonable doubt, and this could be difficult to do in marijuana cases. Experienced Glendale criminal defense attorneys may study toxicology test results and police reports carefully when their clients have been accused of driving while under the influence. They may seek to have drunk driving charges dismissed when the scientific evidence is questionable.

Source: The Arizona Republic, As voters reject Prop. 205, marijuana in Arizona to remain prescription-only, Yvonne Wingett Sanchez, Nov. 8, 2016