In the state of Texas, the police maintain a zero tolerance law. This means that individuals under the age of 21 are not allowed to drive with any alcohol in their system because it is illegal for these individuals to even consume alcohol. Interestingly enough, the "zero tolerance" policy in the state of Texas isn't actually set at 0.00%. In some states, any teen or underage drinker that registers with any alcohol in his or her system can be arrested.
In Texas, the underage drinker has to register at 0.02% to qualify for charges and arrest. This is a very low BAC that most individuals can reach with one or two beers. This means that most of the time teens will be charged with underage drinking and driving if they have had any substantial alcoholic drinks in the recent past. Yet the 0.02% buffer protects any underage individuals who may have only had a few sips of Mom's wine at dinner or had a couple sips of an older friend's beer.
The National Highway Systems Designation Act of 1995 originally mandated that all states consider a 0.02% BAC for under-21 drivers. All states were required to set this limit in order to qualify for Federal Aid Highway Funds. All states eventually agreed to this rule, but many states set their limit as a per se offense. This means that the police don't actually have to prove intoxication as long as the driver is above the stated limit.
Some states decided to go even further and set their limit at 0.00% as later recommended by the federal government. Texas remained at the 0.02% limit, and continues to operate with this law in place today. This means that if you were arrested for an underage DWI and are being prosecuted on a zero tolerance 0.00% policy standard, this may not be in accordance with the state laws. You will want a Houston DWI attorney at The Martinez Law Firm to assist you if you need more information or want to battle your charges.