The two most prominent chemicals in cannabis are cannabidiol (CBD) and tetrahydrocannabinol (THC). THC is primarily associated with the plant’s psychoactive euphoric effects, while CBD is non-psychoactive and has been found to treat various medical conditions from epilepsy to anxiety.

As the medical and non-medical use of cannabis products has become more accepted by mainstream society, the issue of driving under the influence of cannabis products has become quite a contentious public health issue.

In a new study, Australian and Dutch scientists attempted to find out whether CBD alone or in combination with THC, impairs driving ability in real-world conditions. As reported by NewAtlas, the study recruited 26 subjects whose driving performance was tested on four occasions after vaporizing either THC alone, CBD alone, a THC/CBD combination, or a placebo.

The experiment took place on a real highway under controlled conditions for one hour on two occasions: once 40 minutes after vaporizing the drug, and then once again four hours later. In comparison to the placebo, the researchers found there were no driving impairment differences 40 minutes after vaporizing just the CBD. The researchers did, however, detect a mild impairment in both the THC and THC/CBD tests after 40 minutes.

“These findings indicate for the first time that CBD when given without THC, does not affect a subject’s ability to drive,” says Thomas Arkell, lead author on the new study. “That’s great news for those using or considering treatment using CBD-based products.”

It should also be noted that the research detected no driving impairment in any of the four groups who drove four hours after using the vaporizer, affirming previous studies on the matter.