Alcohol is a depressant because it slows down the functions of the central nervous system. When alcohol is consumed, many of the skills that safe driving requires – such as judgment, concentration, comprehension, coordination, visual acuity, and reaction time – become impaired.
Drinking can negatively affect any or all of these crucial driving skills:
Alcohol typically affects the body in a particular sequence. The first part of your body that alcohol affects is the brain, particularly your judgment. This means that your ability to think clearly, reason, plan ahead, and make sound decisions is reduced – even with blood alcohol levels as low as .02 percent.
Even small amounts of alcohol can impair your ability to concentrate on the many tasks that driving entails, and instead leaves you concentrating on only one action.
Unfortunately, when driving you need to focus on several things at once, such as your vehicle position, speed, and other traffic on the road. As soon as you stop focusing on the road, a collision can happen. Many traffic accidents result from a drunk driver who is distracted or who has a short attention span.
Drinking can affect your ability to properly understand or interpret road signs, signals, and situations that you need to respond to quickly in order to be safe on the road. Alcohol may leave you easily confused or unable to respond in an emergency situation.
Drinking can affect both your fine motor skills and gross motor skills, whether it involves putting the key in the ignition or walking to your vehicle. Also, loss of eye/hand/foot coordination can greatly affect your reaction time and your ability to react to a particular situation.
Alcohol can impair your ability to control eye movement and see clearly. It can slow down your eye muscle function and reduce peripheral vision, Studies show that drunk drivers tend to focus on a single point for a long time, and are thus less aware of crucial peripheral areas. Alcohol can also negatively affect your ability to judge depth and distance. You may also find yourself driving with blurred vision, or with impaired color perception and night vision.
6. Reaction Time
Alcohol can slow down your reflexes and decrease the ability to understand and react immediately to changing situations. Studies show that drivers under the influence of alcohol are unable to respond to stimuli as quickly as when they are sober. Due to your impaired comprehension and coordination, your reaction time may slow down by as much as 15 to 25 percent. A decreased reaction time may result in accidents and collisions involving injuries or fatalities.
Alcohol can decrease your ability to judge your position on the road, as well as the location of the centerline, road signs, and of other vehicles around you.
If you or someone you know has had alcohol and are considering getting behind the wheel, do not let them start the engine. All of the above mentioned skills are critical for driving a motor vehicle safely, and should under no circumstances be impaired by alcohol.