**Alcohol** negatively affects driving ability in several ways. One of the most important effects is that it **reduces the field of vision**. This means that when you consume alcohol, you have less ability to see what is happening around you, which can lead to missing traffic signs, traffic lights, or vehicles approaching from the sides.

Additionally, alcohol causes you to misjudge distances and be more easily dazzled by the lights of other vehicles. All of this increases the risk of accidents, as you cannot adequately react to what happens on the road.

Therefore, it is crucial to understand that consuming alcohol before driving not only affects reaction ability but also **significantly reduces the field of vision**, making driving much more dangerous.