Answer: Alcohol
Explanation:
Consumption of alcohol is considered as cause for vehicle accidents. Consuming alcohol before driving a vehicle can tend to cause dizziness, losing mind control,blackout etc and the person can show aggressive and destructive behavior also.
If a drunk person drives any vehicle in such condition then he/she might not be able to maintain coordination and balance of vehicle with the road and other vehicles.Thus, accident is very likely to happen in such condition as attention and focus is lost because of alcohol consumption.