from the link i posted earlier.
Research shows that almost a quarter (22%) of those killed in road traffic accidents (RTAs) in the UK have illegal drugs in their bloodstream, and that there's an increasing number of RTAs where the presence of drugs in a driver's body may have been a contributory factor to the cause of the crash. Drug driving is most common among 20 to 24 year-olds, with clubbers being the most likely to take control of a car in a chemically altered state. In a survey by the Scottish Executive's Road Safety Campaign, 81% of clubbers had driven after recreational drug use, with many believing that cannabis had little or no impact on their driving skills, and some thinking that amphetamine use actually improved their driving skills. Unfortunately, ignorance is far from bliss when it comes to getting behind the wheel while under the influence.
If you think drug-taking has little, or even a positive, impact on your driving you could be tragically mistaken. It's important to bear in mind that it can be hard to determine exactly how a drug will affect your driving ability - impairment caused by drugs can vary according to the individual, drug type, dosage, the length of time the drugs stays in your body, or if the drug has been taken with other drugs or alcohol.
Cannabis
Some people think that cannabis is a 'safer substitute' to drinking, but it can cause concentration to wander, which can affect reaction times. It can also cause paranoia, drowsiness, distorted perception and a sense of disorientation - all of which could cause you to lose control at the wheel.In a study by the Transport Research Laboratory, people who drove a car at 66 miles per hour had a stopping distance of around 270ft, but after smoking a joint this increased on average by 15% to 310ft. In a slalom test, those who had just smoked a joint knocked over 30% more cones.
This isnt opinion, its scientific fact. You dont need to drive and if u do then dont take drugs.