What does 'Zero Tolerance' law mean for drivers under 21?

ZERO TOLERANCE LAWS for underage drivers were enacted because young drivers are statistically more dangerous at any BAC level — their inexperience, developing brains, and higher risk-taking behavior mean that even small amounts of alcohol significantly impair driving ability and decision-making. HOW IT WORKS: All states have zero tolerance laws as a condition of federal highway funding (National Minimum Drinking Age Act requirements); the threshold varies slightly by state: most states use 0.01% or 0.02% BAC for under-21 drivers; this is effectively any detectable alcohol — a single standard drink can raise BAC to 0.02-0.04%; the underage driver can be cited for DUI/DWI at these trace levels that would not be actionable for an adult. CONSEQUENCES for underage DUI are typically: immediate license suspension; fine; mandatory alcohol education program; possible ignition interlock requirement; possible criminal charge (in some states); impact on insurance for years. RELATIONSHIP TO PURCHASING: Zero tolerance applies to DRIVING with any alcohol — the purchasing age laws (21+) are separate and apply to possession and purchasing even without a vehicle. An underage person cannot legally purchase alcohol even if they plan to walk home. THE BROADER POINT: Impaired driving by any driver is dangerous; the zero tolerance law recognizes that underage drivers are uniquely vulnerable to impairment and uniquely prohibited from using alcohol — combining the two creates disproportionate risk.