Addiction Alcohol Use Drunk Driving Why You Should Never Drink and Drive Impairment Begins Long Before You Are Legally Drunk By Buddy T facebook twitter Buddy T is an anonymous writer and founding member of the Online Al-Anon Outreach Committee with decades of experience writing about alcoholism. Learn about our editorial process Buddy T Medically reviewed by Medically reviewed by John C. Umhau, MD, MPH, CPE on December 22, 2020 John C. Umhau, MD, MPH, CPE is board-certified in addiction medicine and preventative medicine. He is the medical director at Alcohol Recovery Medicine. For over 20 years Dr. Umhau was a senior clinical investigator at the National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health (NIH). Learn about our Review Board John C. Umhau, MD, MPH, CPE Updated on December 22, 2020 Print Geber86 / Getty Images Table of Contents View All Table of Contents Legal Limit for Drunk Driving At .02 BAC Level At .05 BAC Level At .08 BAC Level Slower Reaction Time Is There a Safe BAC Limit? It's not a question of whether you are legally intoxicated, it's a question of whether or not it is safe to drive when you have consumed any amount of alcohol. Research shows that impairment begins long before a person reaches the blood alcohol concentration level necessary to be guilty of drunken driving. Legal Limit for Drunk Driving In all 50 states, the legal limit for drunk driving is a blood alcohol concentration (BAC) level of .08. A 120-pound woman can reach a .08 BAC level after only two drinks and a 180-pound man can be at .08 after only four drinks. A "drink" is either one shot of liquor, a five-ounce glass of wine or one beer, all of which contain the same amount of alcohol. At a .08 BAC level, drivers are so impaired that they are 11 times more likely to have a single-vehicle crash than drivers with no alcohol in their system. But 25 years of research has shown that some impairment begins for both males and females even after one drink. At .02 BAC Level At the .02 blood alcohol concentration level, experiments have demonstrated that people exhibit some loss of judgment, begin to relax and feel good. But tests have also shown that drivers at the .02 level experience a decline in visual functions, affecting their ability to track a moving object and experience a decline in the ability to perform two tasks at the same time. While someone with a .02 BAC level might not notice these affects, they can impact how you react (or not react) in an emergency situation while behind the wheel of a vehicle. At .05 BAC Level At the .05 BAC level, people begin to exhibit exaggerated behavior, experience loss of small-muscle control -- such as being able to focus their eyes quickly -- have impaired judgment, lowered alertness and a release of inhibition. If someone with a BAC level of .05 gets behind the wheel, they would be operating the vehicle with reduced coordination, a further diminished ability to track moving objects, more difficulty in steering and a markedly reduced response in emergency situations. At .08 BAC Level When someone drinking is approaching the borderline of legal intoxication, studies show that he or she has poor muscle coordination—affecting their balance, speech, vision, reaction time and hearing—find it more difficult to detect danger and exhibit impaired judgment, self-control, reasoning ability, and memory. A driver with a BAC of .08 will find it more difficult to concentrate, judge the speed of the vehicle, experience reduced information processing capability and exhibit impaired perception. Slower Reaction Time For the person who is drinking, the above impairments may be hardly noticeable at the time, but the slow reaction times that they can produce could prove fatal in an emergency driving situation. That's why it is not a good idea to drive no matter how much or how little you have had to drink. There is another consideration: Alcohol affects people differently. Some people have a higher response to drinking alcohol than others. In other words, people with a high response to alcohol can experience signs of impairment at the .02 BAC level that others do not experience until the .05 level. Is There a Safe BAC Limit? For this reason, in some states, drivers can be arrested for driving while impaired even if their blood alcohol concentration is lower than the legal limit if the law enforcement officer believes he has probable cause based on the behavior and reactions of the driver. It's simply not a wise choice to get behind the wheel no matter how much you have had to drink. The only safe driving limit is .00%. Was this page helpful? Thanks for your feedback! Learn the best ways to manage stress and negativity in your life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Fell JC, Voas RB. The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States. Addiction. 2014;109(6):869–874. doi:10.1111/add.12365 MedlinePlus. Blood alcohol level. Updated July 24, 2018. NHTSA. The abcs of bac. Updated July 2016.