The Phantom Substance: DUIs just got more serious in AZ

Arizona is known for having some of the nation’s most aggressive DUI laws.  A new appeals court ruling has clarified a distinction concerning DUI blood testing for marijuana.

Drivers can be prosecuted for DUI if a blood test demonstrates that they have a chemical compound produced by ingesting marijuana in their blood.     The compound is a remnant indicator that the individual ingested marijuana at some point in the weeks prior, but it does not affect an individual’s ability to function like the metabolite in marijuana.

In the original case, the judge reasoned that individuals that showed no evidence of impairment shouldn’t be prosecuted due to a lack of evidence.

However, the court, on appeal, disagreed.  The compound may not affect the individual’s ability to operate the vehicle but it was evidence that they had ingested marijuana.

The court went on to say that Arizona’s medical marijuana law doesn’t apply to DUI cases.

If you are charged with a marijuana DUI you should consult with an experienced DUI attorney

This ruling poses several possible issues that may become the topic of future cases.

First, the compound has no effect on the individual’s ability to operate a vehicle.  The fact that the compound shows up in blood does not directly demonstrate that the individual was impaired at the time of the traffic stop.

Second, the compound can stay in an individual’s blood for up to a month.  This could mean that an individual traveling from another state, for instance Colorado or Washington, could be prosecuted for DUI even though they had legally ingested marijuana while in the other state.

Third, medical marijuana patients in Arizona could face DUI for operating a vehicle even when they were not actively on the drug.


It is at times like this that it is extremely important to understand your rights and obligations under the law.  In the coming weeks, we will cover a spectrum of items that will better educate you regarding both DUI and your obligations when stopped by law enforcement.

Please continue to consult our blog and  do not hesitate to contact our experienced Tucson DUI lawyers  if you’ve been charged with a marijuana DUI in Tucson at (520) 461-1077 if you have any questions or concerns.