With less than a week until recreational marijuana is legal in Canada, there are concerns about more people driving high.

So how does smoking pot impact your reaction and judgement behind the wheel?

With the help of virtual reality and a medical marijuana user from Vancouver, CTV News conducted an experiment.

Chris Gibson used a simulator to drive the streets of Richmond: "It feels essentially like a real car."

The 28-year-old uses medical marijuana, and said he often drives while under the influence. He doesn't think it really impacts his ability.

To test that theory, he drove a seven-minute virtual course with no weed in his system, then went through the route again after smoking.

"We'll have a leader car for the testees to follow and also we have a guy creating all the mayhem so the testees can react," said Dean Chen, from Axon Driver Solutions.

"We're just curious, we want to see what happens."

Gibson says he smokes 14 joints a day, so for him, the second turn with the driving simulator is " basically the same as everyday driving."

"You don't feel any different having smoked?" CTV's Shannon Paterson asked.

"No, not really," he said. He added he felt less nervous after lighting up.

The software measures his speed and reaction times.

"So the baseline is he has to drive legally and he has to drive safely," Chen explained.

Gibson successfully completed the course. The verdict from the virtual reality driving instructor?

"The first one is definitely more cautious. Second time, after marijuana, you're more relaxed," Chen said.

"Your speed varies a little bit. Also the way you react changed a little bit as well."

Chen said everyone may experience a different effect, but it will still impair some of their abilities.

As a heavy user, Gibson has a high tolerance to marijuana.

"There may be some impact, but not to the point of a new user," he said.

He never feels impaired, he said, so he's not worried about getting behind the wheel.

With a report from CTV Vancouver's Shannon Paterson