Zero Tolerance Law: Underage DUI Laws (2025)

What Is the Zero Tolerance Law?

To understand zero tolerance laws, you must first understand how DUI laws work. Driving under the influence (DUI), also called driving while intoxicated (DWI) or operating a vehicle while intoxicated (OWI), is when someone gets behind the wheel after using drugs or alcohol.

DUI laws consist of two types of violations:

• Impairment offenses occur when drugs or alcohol impair a driver’s skills.
• Per se offenses occur when a driver’s blood alcohol content (BAC) is over the legal limit.

Prosecutors do not need a chemical test to prove an impairment offense. Instead, they need evidence, such as a traffic violation and a failed field sobriety test, that shows the driver’s abilities were impaired. Thus, a driver can face arrest even if their BAC is under the legal limit.

Conversely, prosecutors do not need evidence of impairment to prove a per se offense. The only evidence they need is a chemical test result. Thus, drivers commit a per se offense when they drive with a high BAC, even if their driving skills appear unaffected.

The zero tolerance law applies to drivers under 21 years old. Since 21 is the minimum drinking age, these young people should not have access to alcohol. States can therefore adopt a BAC limit for underage drivers that is at or near zero, hence the name “zero tolerance.”

When an officer stops a driver under age 21, the officer may investigate whether intoxication may explain any traffic violations they witnessed. These observations might give the officer probable cause to perform chemical testing:

• Smell of alcohol
• Bloodshot eyes
• Slurred speech
• Confused responses
• Open cans or bottles of alcohol in violation of the state’s open container law

Zero tolerance laws are per se violations. Thus, prosecutors only need a chemical test that shows a minimal amount of alcohol to convict a young driver.

What Does the Zero Tolerance Law Mean for Drivers Under 21?

Zero tolerance laws have many important effects. First, these laws have radically reduced the incidence of underage drunk driving. According to one study, intoxicated driving by people under 21 dropped by 24.4% after states adopted these laws.

Second, a zero tolerance policy about underage drinking means that minors are at risk of criminal punishment. A zero tolerance arrest, even for a DUI first offense, can result in jail time, fines, probation, and a permanent criminal record.

A DUI lawyer can raise defenses like unreliable chemical testing, and they may be successful. If they are not, a conviction can interfere with a young person’s ability to find employment or win admittance to college.

Third, states have seen the positive impacts of these laws and are applying them to other areas. For example, 12 states also have a zero tolerance law for marijuana.

In these states, a law enforcement officer can arrest a driver under 21 for impaired driving if they have any amount of marijuana in their system. This offense can happen even if the marijuana was legally acquired and did not appear to affect the driver’s abilities.

What Is a Zero Tolerance Policy in Relation to Underage Drinking and Driving in Various States?

The zero tolerance law is in effect for anyone under the age of 21. However, the legal limit for zero tolerance varies from state to state.

For example, Ohio sets this limit at a BAC of 0.02%. This is the amount of alcohol a typical person would absorb into their system after less than one drink. In other words, a young person might be able to take a few sips of beer, wine, or liquor without violating the law. But consuming a full drink could push them over the limit.

On the other hand, Arizona has a true 0 tolerance policy. In this state, a minor commits a crime by driving with “any spirituous liquor” in their body. A chemical test showing a BAC over zero could result in an arrest.

What Is the Liability When Underage Intoxicated Drivers Crash?

The States’ zero tolerance policy for minors and alcohol is related to drunk driving and road safety. However, road safety is enforced by more than criminal punishments; laws also impose civil liability on negligent drivers for the injuries and property damage they cause.

When an underage drunk driver causes a collision, they may have acted negligently by getting into the car after drinking. Under a doctrine called “negligence per se,” crash victims may be able to skip some of the elements of negligence simply by proving the other driver violated drunk driving laws.

Contact ConsumerShield to Learn More

Underage drunk driving can ruin the lives of the young driver and anyone they hit. ConsumerShield helps people understand their rights and find legal representation after a zero tolerance arrest. Contact us for a free case evaluation and a lawyer referral.