Kentucky DUI Laws Explained

By Javier Marín, Editor·Last reviewed September 2026·How we check this

Kentucky codifies driving under the influence under KRS 189A.010. A DUI arrest produces two parallel processes — an administrative KYTC suspension and a criminal case in Kentucky District Court — both moving on separate timelines. Kentucky's Ignition Interlock Device program expanded substantially under the 2020 Igenfritz Law, which now requires IID on a much wider range of DUI cases than the prior law did.

The legal threshold

Adults 21+: 0.08% BAC.
Drivers under 21: 0.02% BAC under Kentucky's zero-tolerance law.
Commercial drivers (CDL): 0.04% BAC.
Impairment charge: Kentucky also charges DUI on impairment evidence below 0.08% — the prosecution must prove the driver's ability was impaired by alcohol, drugs, or controlled substances regardless of measured BAC.

Aggravating factors

Kentucky adds enhanced penalties when:

BAC at or above 0.15% (aggravated DUI under KRS 189A.010(11)).
Operating a vehicle 30+ mph over the limit at the time of arrest.
Driving the wrong way on a divided highway.
An accident causing serious physical injury or death.
Refusal of a chemical test after lawful arrest.
A passenger under 12 in the vehicle.

Aggravated DUI carries a mandatory minimum jail sentence on first offense and significantly longer license suspension than standard DUI.

Administrative suspension

After a DUI arrest where the BAC was 0.08% or higher (or the driver refused chemical testing), the arresting officer typically takes the driver's license on the spot and issues a temporary driving permit valid for 30 days. The KYTC administrative suspension takes effect after 30 days unless the driver requests a hearing within that window:

30 days to 6 months suspension on a first BAC failure.
1 year suspension on a first chemical-test refusal.
1 year suspension on a first aggravated DUI (0.15%+).
Longer for repeat offenders or accidents with injury.

Drivers can apply for a hardship license with IID after a hard-suspension period of 30 days for first BAC offenses or 90 days for refusal cases.

First-offense criminal penalties

A first DUI in Kentucky is a Class B misdemeanor with the following penalties (without aggravating factors):

48 hours to 30 days in county jail (often served as community labor in lieu of jail on first offenses without aggravating factors).
$200 to $500 in base fines, plus court costs and reinstatement fees.
30-day to 6-month license suspension by criminal conviction (concurrent with administrative).
Mandatory completion of a Kentucky Alcohol or Substance Abuse Education program (KASEP, 90 days minimum).
Probation up to 2 years.
SR-22 financial responsibility filing for 3 years — see Kentucky car insurance.

Aggravated first-offense DUI adds a mandatory minimum 4 days of jail time that cannot be suspended.

The Igenfritz Law and IID

Kentucky's Ignition Interlock Device requirements expanded dramatically under House Bill 1 (2020) — known as the Igenfritz Law after the family of a victim killed by a repeat DUI offender. IID is now mandatory for:

All second and subsequent DUI convictions, regardless of BAC.
First DUI convictions with BAC at or above 0.15% (aggravated).
First DUI convictions with a passenger under 12 in the vehicle.
First DUI convictions involving refusal of a chemical test.
Any DUI involving an accident with injury.
Hardship license issuance during any DUI suspension.

The driver pays for installation ($75-$150) and monthly monitoring ($60-$100). The IID provider transmits monitoring data to KYTC monthly. Kentucky's program also offers a discount for indigent drivers — those below 175% of federal poverty level pay reduced fees.

Repeat DUIs

Kentucky uses a 10-year lookback window for DUI enhancement purposes:

Second DUI within 10 years: 7 days to 6 months jail (mandatory minimum 7 days), $350-$500 fine, 12-18 month license suspension, mandatory IID for at least 12 months.
Third DUI within 10 years: 30 days to 12 months jail (mandatory minimum 30 days), $500-$1,000 fine, 24-36 month suspension, mandatory IID for at least 18 months.
Fourth DUI within 10 years: Class D felony — 1 to 5 years in state prison, 60-month suspension, lifetime IID requirement.

Underage zero-tolerance

Drivers under 21 with a BAC of 0.02% or higher face a separate administrative action: 30-day to 6-month suspension on first offense, 1-year suspension on second. The under-21 violation can be charged separately from the criminal DUI. See Kentucky teen license for the broader GDL implications.

Reinstatement

After serving any required suspension period and completing all court-ordered conditions, the driver must pay the KYTC reinstatement fee, install the IID if required, and file SR-22 insurance to be eligible for license reinstatement. See Kentucky suspended license for the full step-by-step process.