According to the National Highway Traffic Safety Administration (NHTSA), drunk driving accidents involving fatalities occur every 40 minutes in the United States.

Alcohol impairs driving – as well as other activities involving coordination – because it works as a depressant on the nervous system. It changes communication patterns of nerve cells in the brain. The impairment of these cells distorts hearing and vision and speech, and dulls the senses and coordination.

While the number of alcohol-related car accidents is high, it has declined in recent decades. The decrease is credited to stronger penalties, increased public education and awareness, and more frequent monitoring by law enforcement. Through sobriety checkpoints, officers can observe random drivers for impairment. Anyone who is driving erratically can also be pulled over and evaluated for intoxication.

One way that sobriety is tested is through breathalyzer testing. When alcohol gets absorbed into the bloodstream, it moves through the lungs and gets expelled by exhaling. The amount of alcohol in the blood is related to the concentration in the air. The ratio of alcohol on the breath to alcohol in the blood is 2100:1; 2100 milliliters of air are equal to 1 milliter of blood.. Breathalyzers work by measuring these levels, called blood alcohol content (BAC.) When an impaired person breaths into the breathalyzer, chemicals in the breathalyzer react with the alcohol to produce a color change. Breathalyzers give instant results without the need to do a blood test.

The use of drugs – even prescription drugs – can also affect driving. Like alcohol, drugs can alter coordination, reaction time, and perception. This includes any over the counter or prescription drug that warns against operating machinery while using. Recent studies show that illegal drugs are used by up to 22% of drivers involved in accidents. Research suggests that marijuana slows a driver’s perception, while cocaine causes drivers to speed and drive erratically.

Several states have laws against driving with any prohibited drug in the bloodstream. Other states define drugged driving as using any drug that causes impairment to the driver.

While drunk driving laws vary by state, every state prohibits driving with a blood alcohol level of .08% or higher. These are called “Per Se” laws. All states also have an Implied Consent Law. This means that anyone with a driver’s license has implied consent to DUI testing. Penalties for driving under the influence include incarceration, vehicle impoundment, revoking of the driver’s license and community service. Because of the repercussions and enormous court fees, it’s important for those arrested for DUI to seek the legal advice of an experienced DUI attorney right away.

Another law recognized in all states is the “Zero Tolerance” law for drivers under the legal drinking age. Underage drivers with any trace of alcohol in their systems can be penalized. The level varies by state. Many states also charge stricter penalties for people with extremely high breath alcohol levels or repeat convictions.

Even small amounts of alcohol can affect driving ability, especially among certain groups like women and older adults.

Alcohol affects women differently than men; dietary guidelines for moderate drinking are two drinks per day per men, but only one for women. Research suggests that more stringent DUI enforcement has resulted in more arrests of female drivers. Alcohol also impairs adults over 50 to a greater degree than their younger counterparts. Older adults become more impaired after drinking moderate amounts of alcohol, without realizing that they are too impaired to drive.

A single drinking and driving incident can have a lifelong impact on many people. While losing a loved one is always difficult, the senseless, violent and sudden loss due to a drunken driving accident is especially profound. When a drunk driver is killed in an accident, family and loved ones have to deal with guilt, shame and social stigma as well as grief. Besides serious legal penalties, drivers who cause alcohol related fatalities have to deal with their guilt for the rest of their lives.