Driving involves many aspects like alertness, concentration and quick reaction. If a person consumes marijuana and starts driving, it will become pretty difficult for him to drive properly.
The person will not be able to concentrate due to drowsiness and it becomes difficult for him to judge the distances. He loses the ability to estimate the time and distance. He will not be able to react to traffic signals and sounds timely. This leads to accidents.
Marijuana affects the nervous system and the person cannot react quickly. For example s/he fails to react to situations and cannot apply breaks when necessary. This may do harm to others who are on other side of the road.
Research shows, marijuana smokers tend to get reckless when driving. This leads to poor concentration and coordination between sight and physical action which leads to fatal accidents.
Research further shows that one-third of the cases of road accidents tested positive for marijuana. Therefore, we can say that marijuana use responsible for accidents. It is therefore advisable not to drive after smoking/consuming marijuana.