How Does Alcohol Affect Driving?

glass of alcohol next to car keys and handcuffs

Most of us know the legal definition of driving under the influence. It’s a blood alcohol content of .08. As long as you are below that, you are okay to drive, right? Wrong!

Alcohol’s effects on the body begin to take place right after you start drinking. You can be charged with a DUI in California, even if you blow under .08! All it takes is for a prosecutor to convince a jury beyond a reasonable doubt that alcohol-impaired your ability to drive.

Read the rest of this blog to learn more about how alcohol affects driving. It may make you reconsider the next time you try to drive after a drink or two.

It Depends

Of course, “it depends” is an answer to most questions, but in this case, it rings true. Alcohol can affect people differently based on a variety of factors. Some factors include:

  • Hydration/Dehydration

  • Weight

  • Sex

  • Hunger

  • Elevation

  • Your Typical Diet

These are just a few of the main elements that affect alcohol impairment. These factors also affect each other. A large male may typically be able to drink two beers without feeling impaired. However, if they’ve changed their diet recently and vacation in Denver, where there is exceptionally high elevation, they may feel buzzed from just half a beer.

The takeaway: be careful if any of these factors may be affecting you differently than usual. Don’t assume you can match someone else drink-for-drink because they don’t seem intoxicated.


Think about how alcohol affects you. It’s usually not seconds after the first shot, right? No, the alcohol needs to be metabolized or broken down by your liver. However, your liver can only do this at a rate of about one drink per hour.

Any excess alcohol during that time will stay in your bloodstream until your liver is ready to break it down and clear it from the body. This is why binge drinking can be so dangerous since multiple drinks in a short period can significantly increase the concentration of alcohol in your blood, causing greater intoxication.

Reaction Time

Study after study has shown what most of know to be true—alcohol affects your reaction time. A 2007 study by Mexican scientists tested reaction times after subjects were given a small amount of alcohol. Even though the amount was small enough to not measurably affect their motor skills, the subjects had slower reaction times.


Alcohol can affect vision. Depending on the amount, drinkers have experienced blurry vision, loss of depth perception, reduced visual field, and difficulty with handling glare. One study showed that at least one of these areas was affected by subjects after they had drunk a significant concentration of alcohol.


Of course, many people know about the effects of alcohol on the body and drink and drive anyways. Why is that? One of the primary factors is that alcohol affects judgment.

People make worse decisions on alcohol and are more likely to give in to their inhibitions. While a sober driver may feel a desire to drive fast, they have the judgment to realize that that is an unsafe idea, and they refrain from it. A drunk driver is much more likely to give in to that impulse.

So, What Can You Do to Help?

Since alcohol affects judgment, how can you make sure that you or your loved ones don’t drink and drive? Make smart choices and plan ahead while sober.

If you are hosting a party where alcohol is being served, consider collecting keys as guests arrive. Designate a sober driver when going out or plan on using a rideshare app. Planning ahead can help you, and your loved ones avoid contributing to the 40% of fatal car crashes that are alcohol-related.

If you or a loved one are ever involved in an alcohol-related car accident, give us at Manning Law a call at (800) 783-5006 for a free consultation. Our Newport Beach car accident attorneys have recovered millions for our clients.

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