There are generally two reasons that people get arrested for drunk driving. The first is for displaying impaired ability while in control of a vehicle. Drivers who can’t safely control their vehicles in traffic or who cause crashes are at risk of arrest.
Police officers can also arrest anyone who fails a chemical test. An elevated blood alcohol concentration (BAC) can be grounds for prosecution even in cases where there is no evidence of diminished driving capabilities.
People who regularly drink may find such rules unfair. Why does the state arrest people based on BAC rather than their performance at the wheel?
BAC correlates to capability
The simplest reason that the state enforces a BAC limit is that higher alcohol levels tend to have a direct association with diminished capabilities. In many cases, drivers who are at or over the legal limit of 0.08% are likely to display clear signs of impaired ability. While some people have higher tolerances, many motorists have difficulty driving safely even before they exceed the BAC limit.
In fact, research out of Utah shows that stricter BAC limits may actually reduce drunk driving offenses and collisions. When motorists are aware that they can face prosecution based not on their performance at the wheel but rather on the results of a chemical test, they may be more cautious about driving after enjoying a few drinks.
Contrary to what people sometimes assume, chemical tests are not 100% reliable and accurate. Those facing charges basically on alcohol levels rather than conduct in traffic may be able to fight pending drunk driving charges. Reviewing the state’s evidence can help those accused of drunk driving evaluate options for avoiding a conviction.