Final answer:
Marijuana is the second most common substance that affects drivers after alcohol. Both can impair essential driving abilities like coordination, reaction time, and judgment, contributing to road accidents.
Step-by-step explanation:
After alcohol, the 2nd most common substance that affects drivers is marijuana. Marijuana's psychoactive effects can impair a driver's ability to operate a vehicle safely. Like alcohol, it can affect coordination, reaction time, and judgment. While alcohol is responsible for a significant number of road accidents due to its sedative effects leading to poor coordination, slurred speech, and impaired judgment, marijuana also causes similar impairments.
It is important for individuals and communities to recognize the risks associated with driving under the influence of any substance, including alcohol and marijuana, to promote road safety for all.