Drivers below the Legal Blood Alcohol Limit Still at Risk for Accidents

Blood alcohol content is a key indicator of a person’s level of intoxication and impairment. In 1993, the legal blood alcohol content was reduced from 0.10 percent to 0.08 percent, and this level is consistent across the U.S. However, many people may not realize they can have seriously impaired levels of thought, reasoning and visual and coordination skills – including those needed to drive a vehicle – when their blood alcohol levels reach 0.04 percent. As blood alcohol content rises, so does the risk of being involved in a car accident.

The term blood alcohol content describes the quantity of alcohol in a person’s blood in terms of weight per unit of blood volume. For example, if a person’s blood alcohol content is 0.10 percent, then alcohol makes up one-tenth of a percent of the person’s blood. Reaching the legal blood alcohol content limit of 0.08 equates to approximately one 12 ounce beverage with an alcohol content of at least 4.5 percent.

However, some studies show that with a blood alcohol content of 0.05 percent, a driver may be two times more likely to be in a car accident than someone who hasn’t consumed any alcohol. While the exact level of connection between lesser blood alcohol levels and driving accidents is still under investigation, studies do show a much higher risk for car accidents is present when the blood alcohol level exceeds 0.08 percent (approximately three drinks).

One of the dangers of alcohol is that it moves quickly to the brain once consumed. Cognitive abilities are affected, often causing car crashes and other accidents. When a person drinks alcohol, it is absorbed partly in the stomach where it then passes on to the blood. The majority of the alcohol content of a beverage is absorbed in the intestines, then taken by the blood to the brain. This is the point at which the drinker begins to notice the “buzz” and other symptoms of drinking.

Additional problems associated with rising blood alcohol content include slow or changed eye activity, meaning a driver cannot estimate distances and driving speed accurately. In comparison to someone who hasn’t been drinking, a drunk driver’s reaction speed can be slowed by 10 to 30 percent. Once the person has consumed enough alcohol to reach a blood level of 0.08 percent, they are ten times more likely to be involved in a car crash. Blood alcohol levels of 0.50 percent or more can bring on coma and a high chance of death; at 1.0 percent, death is certain.

Not only are drunk drivers experiencing impaired judgment, vision and reaction times, they may be less likely to put on a seatbelt and obey traffic laws – factors that make death
from an alcohol-related accident more likely.

Interestingly, women’s bodies absorb and process more alcohol than men – up to 20 percent more. Other factors affecting blood alcohol content include how quickly the person is drinking, and a person’s weight and metabolism. The quicker the drinks are consumed, the higher the levels of alcohol that are stored in the bloodstream. Having eaten before or during drinking slows the effect of the alcohol, as do fruit juices mixed with the alcohol.

As research continues toward the connections between even light drinking and the likelihood of accidents, new regulations could create safer highways and fewer alcohol-related deaths.