Motorists tempted to drive after consuming cannabis have been warned they are putting lives at risk.
Researchers in the US published findings which suggest that driving within three hours of taking the illegal drug almost doubles the risk of causing a vehicle collision, compared with those who are not under the influence of drugs or alcohol.
The research by experts at Dalhousie University, published on bmj.com, involved reviewing nine studies with a total sample of almost 50,000 people.
It comes as figures suggest that rates of driving under the influence of cannabis have increased.
A roadside survey in Scotland found 15% of drivers tested admitted to having consumed cannabis within 12 hours of driving.
It is hoped the authors' conclusion that taking cannabis affects the ability to drive safely will discourage motorists from driving under the influence, less they risk an accident that may cause an injury and will almost certainly affect the premium on theircar insurance policy.
Copyright Press Association 2012