Kentucky DUI Laws

The per se limit is 0.08% for drivers 21 and over, measured by a breath or blood sample taken within 2 hours of when driving stopped (KRS 189A.010(1)(a)). Commercial drivers are deemed under the influence at 0.04% (KRS 281A.210), and drivers under 21 violate a separate offense at 0.02% (189A.010(1)(f)). You can also be convicted of DUI on proof of impairment alone, with no number at all.

Yes. Driving while impaired by ANY substance is DUI (KRS 189A.010(1)(c)), and driving with a listed controlled substance in your blood is a separate per-se count ((1)(d)). A valid prescription is a defense only to the per-se drug count — never to actual impairment ((4)(b)). Marijuana is excluded from the per-se list, but an impaired marijuana user can still be convicted under the impairment counts.

A first offense within 10 years carries a fine of $625 to $925 all-in ($200-$500 base plus the mandatory $425 service fee), OR 48 hours to 30 days in jail, or both — at least one penalty must be imposed and cannot be suspended (KRS 189A.010(5)(a), (9); KRS 189A.050). The $425 service fee is owed in every case, even if jail is imposed instead of the fine. The judge may allow community labor instead. If an aggravating circumstance applies, 4 days in jail are mandatory. The license is suspended for 6 months, reducible to 4 months with an ignition interlock license.

A second offense within 10 years carries a $775-$925 all-in fine ($350-$500 base plus the $425 service fee) AND 7 days to 6 months in jail (KRS 189A.010(5)(b)). An aggravating circumstance raises the mandatory minimum to 14 days, and refusing a breath test doubles the mandatory minimum. The minimum cannot be probated, and at least 48 hours must be served consecutively. The license is suspended for 18 months, reducible to 12 with an ignition interlock license.

A first, second, and third DUI within 10 years are misdemeanors. A FOURTH or subsequent offense within 10 years is a Class D felony punishable by 1 to 5 years in prison, with a 120-day mandatory minimum — 240 days if aggravated — that cannot be suspended or probated (KRS 189A.010(5)(d), (8)(b); KRS 532.060(2)(d)). A third offense carries a $925-$1,425 all-in fine and 30 days to 12 months in jail (60-day minimum if aggravated).

The standard suspensions are 6 months for a first offense, 18 months for a second, 36 months for a third, and 60 months for a fourth or subsequent offense within 10 years (KRS 189A.070(1)(a)2). Each tier has a shorter track — 4, 12, 18, or 30 months — for drivers who get an ignition interlock license and complete the required consecutive violation-free days. Drivers under 18 stay suspended until age 18 if that is longer, and reinstatement requires completing an alcohol or substance abuse program.

Not as part of the sentence — no tier of Kentucky DUI mandates interlock installation. Instead, an ignition interlock license is an opt-in option a suspended driver "may apply" for (KRS 189A.340(2)(a)); it is usually the only way to drive during the suspension and it shortens the suspension if the driver completes a violation-free period. One exception: drivers suspended at arraignment as repeat offenders or after a death or serious-injury crash MUST apply for an interlock license for the pretrial period (KRS 189A.200(3)(b)).

After an alcohol-based DUI suspension, the ignition interlock license is the ONLY license available (KRS 189A.340(1)(a)) — it allows driving anywhere in a vehicle with the device installed. A traditional hardship license (for work, school, or medical needs) exists only for drug-based DUI suspensions under 189A.010(1)(c) or (d) (KRS 189A.410(1), 189A.340(1)(b)), and no hardship license may issue to anyone who refused testing (189A.410(3)).

Your license is suspended by the court at arraignment, before trial (KRS 189A.200(1)(a)). If you are then convicted of a second or third offense within 10 years, refusing the breath test doubles your mandatory minimum jail time (KRS 189A.105(2)(a)1.b), and the refusal is an aggravating circumstance except on a first offense. You also lose all hardship-license eligibility (KRS 189A.410(3)), and even an acquittal does not undo it — a court finding you refused imposes the full conviction-length suspension (KRS 189A.107(2)(b)). Effective July 15, 2026, a breath-test refusal can be used against you in court, while a blood-test refusal cannot.

Ten years, at every tier, measured from offense date to offense date — not conviction dates (KRS 189A.010(5), (10)). The window was extended from 5 to 10 years by the 2016 Brianna Taylor Act. Out-of-state DUI convictions count; under-21 convictions under 189A.010(1)(f) do not. Note the counting window is separate from your record: the conviction itself stays on your driving and criminal record.

Six circumstances aggravate a Kentucky DUI (KRS 189A.010(11)): driving 30+ mph over the limit; driving the wrong way on a limited-access highway; causing a crash with death or serious physical injury; a BAC of 0.15% or more within 2 hours of driving; refusing a breath test (except on a first offense — and for arrests before July 15, 2026, refusing ANY test, breath, blood, or urine); and carrying a passenger under 12. Any one of them converts the tier minimum into hard mandatory jail time — 4, 14, 60, or 240 days by tier — that cannot be suspended, probated, or released early.

A DUI death can be charged as vehicular homicide, a Class B felony carrying 10 to 20 years in prison (KRS 507.060, created by Lily's Law in 2023; KRS 532.060(2)(b)). Prosecutors may instead pursue second-degree manslaughter (a Class C felony, KRS 507.040) or other homicide charges depending on the facts. A death or serious-injury crash is also an aggravating circumstance on the DUI itself (189A.010(11)(c)), triggers license suspension at arraignment (KRS 189A.200(1)(c)), and in a fatal crash officers must seek a blood-test warrant if testing was not done by consent (KRS 189A.105(2)(b)).