A marijuana advocacy group is trying to learn exactly how much marijuana a person can consume before it's unsafe to drive.

To start the process of figuring out the answer, Cannabis Clinicians Colorado hosted a public research event on Sunday at Club Auto Colorado in Lakewood.

“We don’t want our patients driving high,” CCC director Martha Montemayor said. “We don’t want recreational users driving high. We need a better idea of what stoned driving looks like so we can tell people when not to drive.”

The law currently states it’s not safe to get behind the wheel if you have at least five nanograms of THC in your blood system, but Montemayor says there is no science behind that number and it “was pulled out of the air.”

“We inadvertently set up situations like this when we voted to regulate this like alcohol,” Montemayor said.

To help with their research, participants for the study soberly answered questions regarding confidence in their driving abilities at that time. They then underwent a few field sobriety tests as well as blood and saliva tests.

After completing the first round of tests, participants loaded onto a parked bus where they were instructed to smoke until they reached a point they no longer felt comfortable to drive. They then field out the questionnaires and took the field sobriety, blood and saliva tests again. Just to be clear, all participants had to have a designated driver to get home.

It’s too early to know how accurate the study will be in deciding how much is too much for the general population.

Montemayor said the University of Colorado blood lab is helping with the research and the results won’t be ready until October.

The field sobriety tests were recorded and organizers are hoping police departments will use the videos to train officers in what it looks like when someone is too high.