Alcohol is a substance that reduces the function of the brain, impairing thinking, reasoning and muscle coordination. All these abilities are essential to operating a vehicle safely.
As alcohol levels rise in a person’s system, the negative effects on the central nervous system increase, too. Alcohol is absorbed directly through the walls of the stomach and small intestine. Then it passes into the bloodstream where it accumulates until it is metabolized by the liver. Alcohol level is measured by the weight of the alcohol in a certain volume of blood. This is called Blood Alcohol Concentration, or BAC. At a BAC of .08 grams of alcohol per deciliter of blood (g/dL), crash risk increases exponentially. Because of this risk, it’s illegal in all 50 States, the District of Columbia and Puerto Rico to drive with a BAC of .08 or higher. However, even a small amount of alcohol can affect driving ability. In 2016, there were 2,017 people killed in alcohol-related crashes where drivers had lower alcohol levels (BACs of .01 to .07 g/dL).
BAC is measured with a breathalyzer, a device that measures the amount of alcohol in a driver’s breath, or by a blood test.
The Effects of Blood Alcohol Concentration
|BLOOD ALCOHOL CONCENTRATION (BAC) IN G/DL||TYPICAL EFFECTS||PREDICTABLE EFFECTS ON DRIVING|
|.02||Some loss of judgment; relaxation, slight body warmth, altered mood||Decline in visual functions (rapid tracking of a moving target), decline in ability to perform two tasks at the same time (divided attention)|
|.05||Exaggerated behavior, may have loss of small-muscle control (e.g., focusing your eyes), impaired judgment, usually good feeling, lowered alertness, release of inhibition||Reduced coordination, reduced ability to track moving objects, difficulty steering, reduced response to emergency driving situations|
|.08||Muscle coordination becomes poor (e.g., balance, speech, vision, reaction time, and hearing), harder to detect danger; judgment, self-control, reasoning, and memory are impaired||Concentration, short-term memory loss, speed control, reduced information processing capability (e.g., signal detection, visual search), impaired perception|
|.10||Clear deterioration of reaction time and control, slurred speech, poor coordination, and slowed thinking||Reduced ability to maintain lane position and brake appropriately|
|.15||Far less muscle control than normal, vomiting may occur (unless this level is reached slowly or a person has developed a tolerance for alcohol), major loss of balance||Substantial impairment in vehicle control, attention to driving task, and in necessary visual and auditory information processing|
USDOT Releases 2016 Fatal Traffic Crash Data
WASHINGTON – The U.S. Department of Transportation’s National Highway Traffic Safety Administration today released fatal traffic crash data for calendar year 2016. According to NHTSA data, which was collected from all 50 states and the District of Columbia, 37,461 lives were lost on U.S. roads in 2016, an increase of 5.6 percent from calendar year 2015.
The number of vehicle miles traveled on U.S. roads in 2016 increased by 2.2 percent, and resulted in a fatality rate of 1.18 deaths per 100 million VMT – a 2.6-percent increase from the previous year.
NHTSA found that distracted driving and drowsy driving fatalities declined, while deaths related to other reckless behaviors – including speeding, alcohol impairment, and not wearing seat belts – continued to increase. Motorcyclist and pedestrian deaths accounted for more than a third of the year-to-year increase.
The 2016 national data shows that:
- Distraction-related deaths (3,450 fatalities) decreased by 2.2 percent
- Drowsy-driving deaths (803 fatalities) decreased by 3.5 percent
- Drunk-driving deaths (10,497 fatalities) increased by 1.7 percent;
- Unbelted deaths (10,428 fatalities) increased by 4.6 percent;
- Motorcyclist deaths (5,286 fatalities – the largest number of motorcyclist fatalities since 2008) increased by 5.1 percent
- Bicyclist deaths (840 fatalities – the highest number since 1991) increased by 1.3 percent.
NHTSA continues to work closely with its state and local partners, law enforcement agencies, and the more than 350 members of the Road to Zero Coalition to help address the human choices that are linked to 94 percent of serious crashes. NHTSA also continues to promote vehicle technologies that hold the potential to reduce the number of crashes and save thousands of lives every year, and may eventually help reduce or eliminate human error and the mistakes that drivers make behind the wheel.