In Kentucky, as in all states, the legal age for purchasing or possessing alcohol is 21. Driving while intoxicated is against the law for adult drinkers, but the legal definition of intoxicated is different for those over 21 than it is for drivers who are not legally old enough to drink. Most states have zero tolerance laws, or, laws that do not allow a younger person to have even a trace amount of alcohol in his or her system while behind the wheel.

For adults who are over the age of 21, the law in all 50 states allows up to .08 percent blood alcohol for someone who is driving. That means for the average adult, one or possibly two drinks would not make them too drunk to drive legally. But for drivers who are under 21, state laws set the limit at anywhere from 0 to .02 percent. These zero tolerance laws are necessary in order for a state to qualify for Federal-Aid Highway Funds under the National Highway System Designation Act of 1995.

After that law was passed, a study showed that the first 12 states to comply with the zero tolerance law recommendation had a 20 percent decline in fatal car crashes involving underage drivers and that happened at night. Eventually, all 50 states passed zero tolerance laws for underage drinking and driving.

Drinking and driving is not only dangerous, as statistics time and again show, but the legal implications are serious. A first-time DUI could result in fines, jail time and having a criminal record. Legally, there is no arguing that a driver did not appear to be or act drunk; blood alcohol content above the legal limit means that by law, the person was intoxicated. The accuracy of chemical test results, however, can be challenged.