After a few years of driving in New Jersey, a person's muscle memory may automatically take over when behind the wheel. Even though it may seem as if a driver is on autopilot, he or she is constantly making decisions. In fact, according to Johns Hopkins Medicine, the average person makes about 200 choices for every mile driven. For safety, these should be made consciously. If a person drinks alcohol, though, this can be physically impossible.
How does alcohol affect a person's ability to make the necessary choices on the road?
Forbes magazine explains that alcohol changes the way that the chemicals in the brain send messages. Some parts of the brain are suppressed, while others receive a boost. Unfortunately, these mixed messages combine to form some dangerous conclusions.
In the cerebral cortex of the brain, the inhibitors that affect behavior are depressed, impairing judgment and making a person more likely to do something he or she normally would not. Meanwhile, any information coming in visually or audibly is slowed down, and the brain cannot process it well, causing even further issues with decision-making capacity.
Alcohol depresses the medulla, as well, slowing down involuntary functions such as breathing and consciousness. This typically has the effect of making a person drowsy.
When the cerebellum is depressed, people lose full control of balance and movement, causing clumsiness and a lack of coordination.
At the same time that a person's system is becoming dysfunctional, though, alcohol is causing an increase of dopamine. So, while the brain is being shut down by alcohol, a person may feel better than normal and decide that driving will not be a problem. At that point, each choice becomes a threat to everyone else on the road.