How Much Alcohol Can You Have and Drive?

Medically Reviewed on 2/7/2023
Blood Alcohol Content
Any level of alcohol in your bloodstream can impair your ability to drive.

According to CDC, the legal limit for drivers (21 years of age or older) to operate a motor vehicle in the United States is 0.08 percent (80 mg/dL), except for Utah, which established a 0.05 percent legal limit in 2018. However, it is against the law for anyone younger than 21 years to operate a motor vehicle while having any level of alcohol in their system.

Legal restrictions do not specify a limit below which it is secure to drive or carry out other activities. Alcohol consumption can cause impairment even in quantities much below the legal limit.

How does alcohol affect your driving?

Any level of alcohol in your bloodstream can impair your ability to drive. Alcohol addiction can have a variety of negative impacts, increasing the risk of an accident or hurting someone on the road. Concentration, sound judgment, and rapid reflexes are necessary for safe driving. Alcohol impairs these abilities, placing you and others in danger. 

Drinking affects your ability to drive in the following ways:

  • Lack of coordination: Drinking too much affects your ability to coordinate your hands, feet, and eyes. If you don't have the proper coordination skills, you might not be able to prevent a harmful situation. Distinctive signs of poor coordination include difficulty walking, swaying, and an inability to stand straight. After consuming too much alcohol, it can be difficult to even get into and start your car.
  • Slow reaction time: Alcohol impairs your capacity to respond quickly to a variety of situations. Drinking slows down your reflexes, increasing the risk of an accident. As a result, if the car in front of you suddenly breaks or a pedestrian crosses the road, it will take longer for your brain to recognize an emergency and prevent a crash.
  • Decreased vision: Drinking too much alcohol can harm your vision. You can experience impaired vision or lose control of your eye movement after drinking. Your ability to assess the distance between your car and other moving objects on the road may be compromised by vision impairment. Additionally, there can be fewer things in your peripheral vision (what you can see out of the corner of your eyes).
  • Reduced concentration: Alcohol can affect your ability to concentrate, regardless of how much or how little you drink. Several aspects of driving demand your complete attention, which include remaining in your lane, your speed, other vehicles on the road, and traffic signals. Drinking drastically shortens your attention span, which greatly increases the risk of an accident.
  • Impaired judgment: Your judgment of specific conditions is controlled by your brain. Your ability to use judgment when operating a motorized vehicle will be crucial to your decision-making process. For instance, you must be able to anticipate issues and take clear action if another car cuts you off. While driving, your judgment aids in maintaining your attention and awareness of your surroundings.


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How does blood alcohol content (BAC) level affect driving?

Blood alcohol level (BAC) is the amount of alcohol in your blood as a result of drinking alcoholic beverages. The table below summarizes how your BAC level (measured in grams of alcohol per 100 mL of blood) affects your driving:

Table 1. Different BAC levels and their potential effects on an individual
BAC levels (in grams of alcohol per 100 mL of blood) Potential effects
Up to 0.0
  • Talkative, relaxed, more confident
0.05 to 0.08
  • Talkative
  • Acting and feeling self-confident
  • Judgment and movement impaired
  • Inhibitions reduced
0.08 to 0.15
  • Speech slurred
  • Balance and coordination impaired
  • Reflexes slowed
  • Visual attention impaired
  • Unstable emotions
  • Nausea, vomiting
0.15 to 0.30
  • Unable to walk without help
  • Apathetic, sleepy
  • Labored breathing
  • Unable to remember events
  • Loss of bladder control
  • Possible loss of consciousness
Over 0.30
  • Coma
  • Death
Medically Reviewed on 2/7/2023
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