Effects on driving when under the influence of:
Alcohol
Marijuana
Cocaine

When under the influence of alcohol, the human body becomes slower than when sober. Reflexes are impaired and motor skills are almost completely lost. The legal blood to alcohol limit is .08. Anything above that could result in a high costing ticket, a license suspension, and if you are a constant offender, a license revocation. These are just the penalties if you are pulled over for driving drunk, not the possible physical damages that can be done to you or other drivers around you. Even death can occur from drunk driving.
Marijuana has serious harmful effects on the skills required to drive safely: alertness, the ability to concentrate, coordination, and the ability to react quickly. The side effects are very similar to those of being intoxicated. These effects can last up to 24 hours after smoking marijuana. Marijuana use can make it difficult to judge distances and react to signals and sounds on the road. Marijuana may play a role in car accidents. In one study conducted in Memphis, TN, researchers found that, of 150 reckless drivers who were tested for drugs at the arrest scene, 33 percent tested positive for marijuana, and 12 percent tested positive for both marijuana and cocaine.
When cocaine is in the body, it can cause the nervous system to be overly stimulated. When this happens, the senses become to enhanced and the person can experience hallucinations. More symptoms are dilated pupils, an increased temperature, an increased heart rate and blood pressure, a decreased appetite, and an immediate euphoric feeling, including hyper-stimulation, reduced fatigue, and mental clarity, All of which can impair ones driving and keeps you from being 100% behind the wheel.

This chart explains the legal amount of alcohol that is allowed in a person’s blood.
From levels .04-.06, the brain becomes dehydrated and simple motor skills seem like impossible tasks. After .07 on, you are legally not allowed to drive because of the extreme damage done to your body. Being drunk makes it difficult to walk, determine depth, and stay focused on the road.

Teenagers and driving under the influence-
Teenage drunk driving kills eight teens every day.
Approximately 1,500 teens die each year from drinking and