Any amount of alcohol in your system starts to impair you. Even with a blood alcohol level of only .02, you probably feel more relaxed than normal and your judgment is slightly impaired. By the time you reach .08, though, the impact can be much more severe.
Commonly, at .08 blood alcohol level, individuals experience poor muscle coordination. That doesn’t just mean you stumble a bit. It also means your reaction time is worse than normal and your senses, including vision and hearing, can be impaired. Since speech is governed by many small muscle movements, you begin to slur words.
Concentration and short-term memory are impacted at this point, making it difficult to engage in any type of complex activity. While driving a motor vehicle doesn’t seem like a complex task because of our daily familiarity with it, it actually requires a lot of coordinated movement and concentration to do safely. You might also have trouble controlling the speed of the vehicle if your blood alcohol level is high.
Finally, a high blood alcohol level makes it difficult to detect and properly respond to dangerous situations. You might take risks on the road that you would not otherwise take if you drive with a high blood alcohol content. Because you can’t be sure where your BAC stands without testing it, it’s obviously better not to drive after drinking.
It’s important to note that these symptoms are general, and everyone’s body reacts to alcohol in different ways. You could have a single drink, not feel any of these symptoms and still test for a BAC above the legal limit. BAC levels are also inconsistent, so if you face a DWI charge based on a blood alcohol content test, consider speaking with a lawyer about your options for a defense.
Source: Mothers Against Drunk Driving, “Understanding .08,” accessed July 15, 2016