The legal BAC to drive in the United States is 0.08% for most adult drivers, with Utah being the only state that sets the limit lower at 0.05%.1Utah Highway Safety Office. 0.05 BAC Law Commercial drivers are held to 0.04%, and drivers under 21 face a zero tolerance standard of 0.02% or lower in every state. These numbers are “per se” limits: a chemical test at or above the threshold is enough on its own to convict you, with no further proof of impairment required.
The 0.08% Rule for Standard Adult Drivers
In 49 states and the District of Columbia, driving with a BAC of 0.08% or higher is automatically illegal. Prosecutors do not need to show that you were weaving, slurring, or driving badly. The test result is the case. Federal law pushed states into adopting this uniform number by tying highway funding to it under 23 U.S.C. § 163, which lets the Secretary of Transportation withhold money from states that fail to make 0.08% a per se offense.2Office of the Law Revision Counsel. 23 U.S. Code 163 – Safety Incentives to Prevent Operation of Motor Vehicles by Intoxicated Persons
Utah broke from the pack in December 2018, becoming the first and still the only state to drop its per se limit to 0.05%. Other states have introduced similar bills, but none have passed as of early 2026. If you are driving through Utah, 0.05% is the number that applies regardless of where your license was issued.
You Can Be Charged Below the Legal Limit
This is the point most drivers get wrong. The 0.08% threshold is a floor for automatic prosecution, not a safe harbor. Officers in every state can arrest you for impaired driving at 0.06%, 0.04%, or lower if your behavior shows alcohol is affecting your driving. Failed field sobriety tests, erratic lane changes, slurred speech, and slow reaction times can all support a charge when the breathalyzer reads well under the limit. Without the per se number the prosecution’s job is harder, but the charge is on the table.
The same logic covers drugs. Every state prohibits driving while impaired by marijuana, opioids, methamphetamines, prescription medications, or over-the-counter drugs that affect your ability to drive.3National Highway Traffic Safety Administration. Drug-Impaired Driving Most states have no numeric per se standard for drugs. The case rests on observed impairment plus toxicology showing the substance in your system.
Lower Limits for Younger and Commercial Drivers
Drivers Under 21
Every state has had a zero tolerance law since 1998. These laws cap BAC at 0.02% or lower for anyone under 21.4National Highway Traffic Safety Administration. Zero-Tolerance Law Enforcement The small allowance above absolute zero accounts for instrument error, not for a drink. Penalties typically include immediate license suspension and can follow the driver into adulthood through insurance surcharges and a permanent mark on the driving record.
Commercial Driver’s License Holders
If you hold a CDL, the per se limit drops to 0.04%, roughly half the standard adult number. Federal law sets this threshold and it applies whether you are hauling freight, driving a school bus, or operating any vehicle that requires a CDL.5Office of the Law Revision Counsel. 49 U.S. Code 31310 – Disqualifications
The federal consequences stack on top of state criminal penalties:
- First offense: one-year disqualification from operating any commercial vehicle. If the driver was hauling hazardous materials, the disqualification jumps to three years.
- Second offense: lifetime disqualification, with possible reinstatement after a minimum of ten years.
The rule covers the person, not just the vehicle.6eCFR. 49 CFR 383.51 – Disqualification of Drivers A CDL holder convicted of a standard DUI in their personal car on a weekend still faces the one-year commercial disqualification.7Federal Motor Carrier Safety Administration. Is a Driver Disqualified for Driving a CMV While Off-Duty With a Blood Alcohol Concentration Over 0.04 Percent?
Implied Consent and Refusing the Test
All 50 states have implied consent laws. By operating a vehicle on public roads you have already agreed to submit to a chemical test when an officer has lawful grounds to suspect impaired driving.8National Highway Traffic Safety Administration. Traffic Safety Facts – Laws – Implied Consent You can still say no. The penalties for refusing are usually worse than those for failing.
Refusal typically triggers an automatic administrative license suspension longer than the one for a failed test. A first refusal commonly means a one-year suspension, compared to 90 days for a first failed test. Repeat refusals can bring multi-year suspensions or permanent revocation. In roughly a third of states, refusing is a separate criminal offense on top of the DUI charge. In every state, the refusal itself is admissible at trial, and prosecutors will argue you refused because you knew the result would be incriminating.
You Do Not Have to Be Driving
A common and expensive misconception is “I wasn’t driving, so I can’t get a DUI.” Most states define the offense as driving or being in actual physical control of a vehicle while impaired. You can face charges while parked in a parking lot, sitting at a red light, or sleeping in the driver’s seat with the engine running. Courts look at the totality of the circumstances: where the keys were, whether the engine was on, what gear the car was in, whether the hood or tires were warm from recent driving.
If you need to sleep off alcohol in your car, the safer position is in the back seat with the keys out of the ignition. That is not a guarantee in every jurisdiction, but it makes the physical control argument much harder for prosecutors to win.
Aggravating Factors That Make Things Worse
Not all DUI charges are equal. Several circumstances push a standard misdemeanor into enhanced or felony territory, with higher fines, mandatory jail time, and longer license suspensions.
High BAC
Most states impose stiffer penalties when BAC reaches a second, higher threshold. The most common trigger is 0.15%, used by roughly half the states, with others drawing the line at 0.16%, 0.17%, or 0.20%.9National Conference of State Legislatures. Increased Penalties for High Blood Alcohol Content Crossing into the high-BAC tier typically means mandatory jail time, longer suspension, and a required ignition interlock device even on a first offense.
Child Passenger
Driving impaired with a minor in the vehicle is a separate aggravating factor in many states. Enhanced penalties commonly include additional mandatory jail time, higher fines, and in some jurisdictions a referral to child protective services. Several states treat this scenario as an automatic felony regardless of prior history.
Repeat Offenses and Felony Elevation
A first DUI is typically a misdemeanor. The charge escalates to a felony based on the number of prior convictions within a state’s lookback period, which ranges from five years to lifetime. The most common felony trigger is a third or fourth DUI within that window. A DUI causing serious injury or death is nearly always charged as a felony regardless of prior history.
What the Penalties Actually Cost
DUI consequences vary by state, but a first-offense conviction for an adult generally lands on three fronts at once: criminal, administrative, and financial.
Criminal Penalties
A first offense is usually a misdemeanor carrying possible jail time from a couple of days to six months, fines between roughly $500 and $2,000 before court costs, and a probation period that may include mandatory alcohol education. Second and third convictions escalate sharply, with mandatory minimum jail sentences measured in months, fines in the thousands, and multi-year or permanent license revocation.
License Suspension
The DMV (or equivalent agency) acts independently of the criminal case. Failing a chemical test usually triggers an automatic suspension of 90 days to one year for a first offense. These administrative actions frequently take effect within days of the arrest, well before the criminal case reaches a courtroom. Many states require a substance abuse assessment or alcohol safety program before driving privileges are restored.
Ignition Interlock Devices
A growing number of states require an ignition interlock device, including for many first-time offenders. The device requires you to blow into a breathalyzer connected to the ignition before the engine will start, with periodic retests while driving. Installation typically runs $70 to $150, with monthly lease and monitoring fees of $50 to $120. A mandatory interlock period usually lasts six months to two years depending on the offense.
Insurance and Long-Term Costs
The financial hit that surprises most people is auto insurance. After a conviction, most states require you to file an SR-22 certificate of financial responsibility, generally for three years though some states require longer. The filing itself is cheap, but the conviction behind it typically doubles your premiums. A DUI stays on your driving record for three to ten years depending on the state, and the elevated premiums persist for most of that period.
Add it up — fines, court costs, private attorney fees of roughly $1,500 to $7,500 on a first-offense case, alcohol education programs, interlock expenses, higher insurance premiums over several years, and lost wages from jail time or court appearances — and a first DUI frequently costs $10,000 or more. Repeat offenses are exponentially worse, before even accounting for the career damage of a felony conviction or a permanently revoked license.