How Dope Affects Driving

Hallucinations

Research is sparse, but Huestis says pot-related cases can happen and are an “underappreciated” threat on the road.

Slower decisions

Being high can impair users’ executive function and problem-solving ability. That makes it harder for drivers to make a smart choice–do I swerve or slam on the brakes?–on the fly.

Reduced awareness

Brain imaging shows that it’s harder for people who are high to focus on several things at once, such as a changing stoplight, an approaching bicycle and a car signaling a turn.

Limited vision

“It’s harder to see events in your periphery,” says Huestis, referring to the tunnel-vision effect of pot, which impairs drivers’ ability to recognize obstacles to their far left and right.

Sluggish reflexes

Pot can negatively affect the parts of the brain that coordinate and initiate movement, which makes it tougher to physically control a car.