getting behind the wheel within three hours of smoking cannabis could almost double the risk of a serious crash, research suggests.
A review of nine studies involving 49,000 drivers in accidents found they were more likely to be in a collision with another car after using the class B drug.
Figures show there are around a million users of cannabis in the UK aged 16 to 24 – double the number for the 16 to 59 age group.
Today’s research from Canada, published in the British Medical Journal, found cannabis use resulted in a “near doubling of risk of a driver being involved in a collision resulting in serious injury or death”.
Previous studies have suggested that cannabis impairs a person’s mental abilities and the tasks needed for safe driving. The experts added: “The results also accord with recent data for collisions that point to the increasing presence of drugs other than alcohol (especially cannabis and depressants of the central nervous system) in injured and fatally injured drivers.”
In 2007, a roadside survey in Scotland found that out of 537 drivers tested, 15 per cent admitted to having taken cannabis within 12 hours of driving.
Martin Barnes, chief executive of DrugScope, said: “This research paper confirms what the available evidence has suggested for some time: driving while under the influence of drugs such as cannabis can be dangerous.”
Road safety Minister Mike Penning said: “Drug-driving is a menace which is why we are going to introduce a new drug- driving offence and drug-screening equipment to make it easier for the police to test for the presence of drugs and crack down on this irresponsible minority.
“Britain has some of the safest roads in the world but we are not complacent and I am determined to crack down on those who recklessly risk the lives of others.”