**Alcohol** negatively affects driving ability, especially **vision**. When you consume alcohol, it is distributed throughout the body via the bloodstream and has a significant impact on the brain and vision. This is dangerous because vision is crucial for receiving most of the information needed to drive safely, such as road conditions, traffic signs, and the distance to other vehicles.

Alcohol consumption reduces the ability to see what is happening to the sides and behind the vehicle, known as the **field of vision**. This means the driver may not adequately perceive traffic signs, traffic lights, and the distance to other vehicles. Additionally, alcohol can cause glare from other vehicles' lights and increase the likelihood of distractions.

Therefore, alcohol **can indeed decrease the driver's field of vision**, which increases the risk of accidents.