The drink drive limit in the US and the UK lines up more closely than the different units suggest. In 49 US states and the District of Columbia, the limit is 0.08% blood alcohol concentration (BAC); in England, Wales, and Northern Ireland, it is 80 milligrams of alcohol per 100 milliliters of blood, which is the same concentration written a different way. The outliers go lower by the same amount: Utah sits at 0.05% BAC, and Scotland at 50mg per 100ml. The headline numbers match. Almost everything around them — testing, penalties, how long a conviction follows you — does not.
The Limits Side by Side
American law reports BAC as a percentage of the bloodstream. 0.08% means 0.08 grams of alcohol per 100 milliliters of blood, which converts to 80mg per 100ml. A driver at the legal limit in New York would be at the legal limit in London. Scotland’s 50mg is equivalent to 0.05% BAC, so the strictest limits in each country happen to be identical even though the two jurisdictions arrived at the number independently.
In the US, every state sets 0.08% because federal law withholds a share of highway funding from any state that does not.1Office of the Law Revision Counsel. 23 USC 163 – Safety Incentives to Prevent Operation of Motor Vehicles by Intoxicated Persons Utah broke from the pack in 2018 to become the first and only state at 0.05%.2Utah Highway Safety Office. Utah Highway Safety Office – 05 BAC Law A 180-pound man generally reaches 0.08% after about four standard drinks over two hours; 0.05% is closer to two or three.
The UK has no single national limit. England, Wales, and Northern Ireland use 80mg, a figure that has stood since 1967 and is one of the highest in Europe.3GOV.UK. The Drink Drive Limit Scotland dropped to 50mg in December 2014 to align with most of Europe.4Scottish Government. Drink-Drive Limit – Policy Crossing the border from England to Scotland means complying with the lower figure immediately. The UK also measures alcohol by breath and urine, with proportionate thresholds; breath is 35 micrograms per 100ml in England, Wales, and Northern Ireland, and 22 micrograms in Scotland. Exceeding any one measure is an offense under Section 5 of the Road Traffic Act 1988.5Legislation.gov.uk. Road Traffic Act 1988, Section 5
If you are used to the American percentage, divide the UK blood figure by 1,000 to convert: 80mg becomes 0.08%, 50mg becomes 0.05%.
Who Faces a Lower Limit
Both countries tighten the rules for higher-risk drivers, but they target different groups.
In the US, federal regulations cap BAC at 0.04% for anyone operating a commercial motor vehicle, including large trucks, buses, and vehicles hauling hazardous materials. A first violation brings a one-year disqualification from commercial driving, three years if hazardous cargo was involved, and a second offense means a lifetime ban.6eCFR. 49 CFR 383.51 – Disqualification of Drivers Drivers under 21 face zero-tolerance laws in every state, with the limit set below 0.02% BAC and some states at 0.00%.7NHTSA. Zero-Tolerance Law Enforcement
The UK does not set separate road limits for commercial drivers or new license holders. A lorry driver and a learner share the same 80mg (or 50mg in Scotland) threshold. The lower limits in the UK sit in other transport sectors. Pilots and air traffic controllers must stay under 20mg per 100ml of blood, a quarter of the road limit.8Legislation.gov.uk. Railways and Transport Safety Act 2003, Part 5 Rail workers have their own restrictions under the same legislation.
If You Refuse a Test
Refusing to be tested is not a workaround in either country.
Every US state has an implied consent law: by driving on public roads, you have already agreed to submit to a breath, blood, or urine test if an officer has reasonable suspicion of impairment.9NHTSA. BAC Test Refusal Penalties All states except Wyoming impose separate administrative penalties for refusal — commonly an automatic license suspension that often lasts longer than you would have faced for simply failing the test. In at least a dozen states, refusal is itself a criminal offense on top of any DUI charge.
In the UK, Section 7 of the Road Traffic Act 1988 lets police require breath specimens during an investigation, and refusing without reasonable excuse is itself an offense.10Legislation.gov.uk. Road Traffic Act 1988, Section 7 A preliminary roadside breath test is followed by an evidential test at the police station.11GOV.UK. Being Stopped by the Police While Driving – Breath Tests Failing to provide a specimen at the station carries the same penalties as drink driving: up to six months in prison, an unlimited fine, and a minimum 12-month ban. It also brings automatic classification as a “high risk offender,” which adds hurdles to getting your licence back.
Penalties If You Are Over the Limit
This is where the two systems diverge most sharply. US penalties are set state by state; UK penalties are nationally consistent, and Scotland follows the same sentencing framework despite its lower limit.
US
A first DUI is typically a misdemeanor combining fines, license suspension, possible jail time, probation, and mandatory alcohol education. Specifics turn on the state, the driver’s BAC, and whether anyone was hurt. Many states now require ignition interlock devices even for first-time offenders; as of 2024, 31 states and the District of Columbia mandate interlock installation after a first conviction. The device requires a clean breath test before the engine will start. Repeat offenses escalate rapidly toward felony charges.
UK
Driving or attempting to drive while over the limit in England and Wales carries up to six months in prison, an unlimited fine, and a minimum 12-month driving ban. A second conviction within 10 years raises the minimum ban to three years.12GOV.UK. Drink-Driving Penalties Drivers classified as high risk offenders must pass an independent DVLA medical examination before their licence can be reissued once the ban ends. The exam includes a blood test for carbohydrate deficient transferrin (CDT), a biomarker of sustained heavy drinking. Because driving is not allowed during the medical process, drivers are advised to start the re-application 90 days before the ban expires.
Insurance and the Long Tail
Court penalties are only the start. In the US, a first-time DUI raises car insurance premiums by an average of roughly 88%, with the increase lasting three to five years. Many states require an SR-22 certificate, which the insurer files with the state to confirm minimum coverage; the filing itself runs around $25, but the policy behind it is a high-risk policy priced accordingly. License reinstatement fees add another $100 to $500 on top of fines, legal costs, and treatment programs.
In the UK, premiums routinely double or more after a conviction, and some insurers refuse to cover convicted drink drivers at all. The endorsement stays on your licence for 11 years from the date of conviction, and insurers can see it the entire time.
How Long a Conviction Stays With You
In the US, how long a DUI stays on your driving record depends on the state. Most keep it for 10 years. A handful, including Colorado, Delaware, Illinois, Massachusetts, Texas, and Vermont, keep it on the driving record permanently. On the criminal side, a DUI usually remains on your criminal record indefinitely unless you successfully petition for expungement or sealing, which some states allow for first-offense misdemeanors after a waiting period and others, like Illinois, specifically exclude.
In the UK, the drink driving endorsement code (typically DR10) stays on the licence for 11 years. The conviction itself becomes “spent” under the Rehabilitation of Offenders Act after five years if the sentence was a fine and endorsement, meaning most employers and applications no longer need to be told.
Traveling Between the Two Countries With a Conviction
A drink driving record can follow you across the Atlantic. UK citizens with a conviction who want to visit the US should know that the US Embassy in London has stated plainly that the Rehabilitation of Offenders Act does not apply to US visa law: even a spent conviction must be declared.13U.S. Embassy & Consulates in the United Kingdom. Ineligibilities and Waivers If the conviction involved an arrest, the Embassy advises against traveling under the Visa Waiver Program (ESTA) and recommends applying for a full visa instead.
Canada is harder. A single DUI from either country can render a traveler inadmissible as a serious criminal offense, and rehabilitation applications are only available at least five years after the sentence has ended.14Government of Canada. Convicted of Driving While Impaired
Travelers entering the UK must disclose overseas convictions on visa applications. A drink driving conviction that resulted in a custodial sentence of 12 months or more triggers mandatory refusal. Shorter or non-custodial sentences leave the decision to immigration officer discretion, and a single conviction without imprisonment is unlikely to lead to refusal for most visitors.15GOV.UK. Suitability – Grounds for Refusal / Cancellation – Criminality