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Minnesota Driving LawsFirst the Breathalyzer, now the ‘Weedalyzer?’

As more states pass legislation legalizing marijuana for medical and recreational purposes, health and law enforcement officials await technology that can quickly determine when drivers are too stoned to drive safely.

However, unlike a breathalyzer used to detect drivers suspected to be under the influence of alcohol, police do not yet have a reliable device that can be used to scientifically determine if a driver is impaired byTHC – the impairing component of cannabis.

In order to prove that a driver was impaired by marijuana, police must now rely on their own observations of the physical appearance of the driver, the driving conduct and the driver’s performance on field tests conducted by an officer trained as a drug recognition evaluator (DRE).

Although drug testing methods that examine blood, saliva, or urine may be used, none can determine whether the cannabis use was recent or prove that the THC detected in a person's system caused impairment at the time of testing. Unlike alcohol, marijuana can remain in an individual’s system for hours, if not days, long after the intoxicating effects have worn off.

Despite a need from law enforcement, development of a cannabis breathalyzer (‘weedalyzer’) has yet to be perfected. However, several companies and scientists have been working on such a device to test drivers for marijuana impairment, claiming new advancements in methods of detecting and capturing and analyzing THC in breath. 

Recently, a study at the University of California-San Francisco study suggested that THC could be detected in breath for up to three hours post-consumption and that a correlation exists between measured THC concentrations and blood concentrations during that time.

The study was sponsored by Hound Labs, an Oakland, California company that is in the process of developing a dual alcohol and THC breathalyzer that will attempt to measure particles in breath to show if a person consumed cannabis within three hours prior to testing.

Last year, researchers at University of Pittsburgh researchers issued a press release regarding refinements toa technology that allowed themto identify THC particles in breath samples. The researchers are currently seeking financial backing to develop a portable THC breathalyzer utilizing this technology.

Some polydrug tests have already reached the marketplace. For example, the SoToxahandheld rapid mobile drug screening test can purportedly detect up to six different drugs from cannabis to cocaine to prescription medications within five minutes of analyzing a saliva sample. Developed by healthcare company Abbott, the device is presently being used in Canada, Spain, Michigan, Alabama and Oklahoma.

But because marijuana and alcohol don’t affect the human body in the same way physiologically, and because marijuana impairment levels vary among individuals, it is doubtful thata reliable baseline for marijuana "intoxication" can be scientifically established.

Currently, there is no uniform agreement among the states regarding how much of a THC concentration found in an individual’s system should be considered impairing or illegal. Consequently, laws regarding marijuana impairment while driving vary from state to state.

While all states have ‘per se’ blood limits for alcohol concentration (0.08 with the exception of Utah which is 0.05) only five states (Illinois, Montana, Nevada, Ohio, and Washington) prohibit driving with a detectable amount of TCH that exceeds a specific legal limit. Colorado has a ‘permissible inference’ law which allow a rebuttable presumption that a driver is impaired if his or her THC blood level is measured in a quantity of 5ng/ml or higher.

Thirteen other states (Arizona, Delaware, Georgia, Illinois, Indiana, Iowa, Michigan, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Utah, and Wisconsin) have passed ‘zero tolerance’ laws prohibiting driving with any amount of THC and/or its metabolites in the body.

Minnesota and the remaining states require proof that driver was actually under the influence of or affected by THC in order to be convicted of impaired driving by marijuana.

While companies rush to develop and market a new ‘weedalyzer’ device for law enforcement purposes, it appears that the usefulness of such a device will be solely limited to detecting THC molecules in a person's breath and not whether the THC analyzed correlates with impairment.

If you find yourself facing marijuana DWIcharges it is extremely important to have an experienced attorney who will challenge the evidence being used against you and explain your best options for getting your driving privileges restored as soon as possible. Attorneys are available 24-7 — Call us at 612-334-3342.