AAA Safety Foundation Finds No Scientific Basis that THC in Blood Impairs Driving

A study from motor club AAA's safety foundation found that testing for THC through blood is not even scientifically possible.


Does THC show up in blood tests?

States with legalized marijuana have already begun testing driver’s blood for THC. The blood testing is used to determine whether or not the driver is impaired. New research says this is a problem. A study from motor club AAA’s safety foundation found that testing for a “high” through blood is not even scientifically possible. So, high drivers may be getting let off the hook, and sober ones could be getting unfairly punished.

AAA Blood Alcohol Testing Vs. THC Testing


When a drunk driver is being tested for alcohol, we can be confident from the results whether or not the driver drank before driving. Mostly because of scientific testing. The THC tests being used are a different story.

“There is understandable a strong desire by both lawmakers and the public to create legal limits for marijuana impairment, in the same manner, we do alcohol,” said AAA president and CEO, Marshall Doney. “In the case of marijuana, this approach is flawed and not supported by scientific research.”

The study notes that impairment from THC is very different than with alcohol. Regular cannabis users can have high blood levels of THC, even if they aren’t high.

AAA recommends specialized training for law enforcement to determine better whether or not a user is impaired from their behavior. Then, a blood test to confirm the presence of THC. Many are against AAA’s recommendation.

THC Blood Testing In States With Legalized Marijuana


Nine states, including some with medical marijuana laws, have a zero-tolerance policy when it comes to stoned driving. Some of them even test for metabolites, which can remain in the blood well after your last joint.

These laws have received heavy criticism from experts. New York University professor and specialist in drug issues and criminal policy, Mark A. R. Kleiman says testing for THC impairment through blood makes no sense.

“A law against driving with THC in your bloodstream is not a law you can know you are obeying except by never smoking marijuana or never driving,” he explained.

Kleiman doesn’t seem too threatened by stoned drivers. In fact, he thinks “a noisy child in the back of the car” is just as dangerous as driving on weed. Finally, he disagrees with AAA’s recommendation for specialized law enforcement and thinks it should just be treated as a traffic violation.

AAA’s recommendation still makes it very possible for accidental prosecution. Legislation that has potential to send innocent people to jail shouldn’t be in place.

Final Hit


One possible alternative to testing blood for THC would be the pot breathalyzer designed by Hound Labs. California police tested the device on drivers who were surprisingly open about their recent marijuana usage. Officers pulled over drivers who were driving irregularly. Those who claimed to have smoked within the past two or three hours came up positive for recent marijuana usage on the breathalyzer.

With current technology, sober drivers can still face arrest for cannabis that was smoked a week prior. If marijuana users are going to be tested for impaired driving, a more accurate analysis needs to be found.

" Ab Hanna : @ Ab is an East Coast editor for Green Rush Daily. He enjoys learning new information about cannabis and cannabis products through research and experience. His work is also featured in High Times Magazine.."