by Robert Shearouse

About the author: Robert Shearouse is the national director of public policy for Mothers Against Drunk Driving.

The 21-year-old minimum drinking age has been the law nationwide since 1986. Several states actually adopted “21” laws before that time and it’s estimated that such laws have saved more than 16,500 lives since 1975.

But until recently, it wasn’t against the law in many states for drivers under 21 to drink and drive. This conduct wasn’t deemed illegal for young drivers until their blood alcohol content (BAC) exceeded the illegal drunk driving limit established by each state for all drivers—either .08 or .10 percent BAC.

Zero Tolerance Saves Lives

In 1995, Congress passed legislation requiring all states to adopt “zero tolerance” laws for drivers under...