Reaction time is slower after:

Consuming alcohol significantly impairs cognitive functions and physical coordination. When a person drinks alcohol, the central nervous system is affected, leading to delayed reactions and slower processing of information. This impairment increases the time it takes to respond to stimuli on the road, which can be critical in driving situations where quick reaction is necessary to avoid accidents.

While heavy meals or certain medications like cold medicine can also influence reaction time, the effects of alcohol are particularly pronounced and well-documented in affecting both motor skills and judgment, which are vital for safe driving. Regular consumption of caffeine typically enhances alertness, making it less likely to slow reaction time. This makes alcohol the most concerning factor when it comes to diminishing reaction capabilities while driving.