**Alcohol** negatively affects the driver in several aspects, including **reaction time**. When a person consumes alcohol, they need more time to process information and make decisions at the wheel. This is because alcohol affects the ability to coordinate movements and assess the environment, which can lead to a **slower reaction** to unforeseen events.

**Reaction time** is the interval between perceiving a stimulus, such as a red traffic light, and responding to it, for example, by braking the car. Under normal conditions, this time is approximately half a second to a second. However, alcohol consumption prolongs this time, thus increasing the **reaction distance**. This means that the vehicle will cover more space before the driver can react appropriately.

Therefore, alcohol not only increases reaction time but also raises the risk of accidents by not being able to respond in time to dangerous situations.