Most people believe Kentucky has a single DUI limit — a blood alcohol concentration (BAC) of 0.08%. That is the number that applies to most adult drivers, but it is not the only one. Kentucky actually sets three different limits, and which one applies to you depends on your age and what you are driving.
I am attorney Jay Fleenor, and I defend people facing DUI charges throughout Southeastern Kentucky. Knowing which limit applies to you — and understanding that the number is not the whole story — matters from the moment of the stop.
0.08% for most adult drivers
For drivers 21 and older, the limit under KRS 189A.010 is a BAC of 0.08%. This is a per se limit: if your BAC is at or above 0.08%, that alone can support a DUI conviction — the Commonwealth does not have to separately prove that your driving was impaired. The number itself is the offense. This is a common misunderstanding in DUI cases, and it is why the accuracy of the breath or blood test matters so much.
0.04% for commercial drivers
If you hold a CDL and you are operating a commercial vehicle, your limit is cut in half, to 0.04%. For a commercial driver, the stakes reach well beyond the criminal case. A DUI is a major offense that carries a one-year CDL disqualification on a first conviction — and because a commercial conviction cannot be masked with diversion or traffic school, you cannot keep it off your record the way another driver sometimes can. For someone whose livelihood is behind the wheel, that can mean lost income long after the case itself is resolved.
0.02% for drivers under 21
For anyone under 21, the limit drops to 0.02%. Because no one under 21 can lawfully drink in the first place, Kentucky applies a near-zero-tolerance rule — 0.02% can be reached after a single drink. One important caution for young drivers and their parents: if an under-21 driver’s BAC is 0.08% or higher, they face the same penalties as an adult, not the lighter underage provision.
The number is not the whole story
Here is what the three limits can obscure: you can be charged and convicted of DUI even when your BAC is below the applicable limit. Kentucky law also makes it an offense to drive while actually impaired by alcohol, a controlled substance, prescription medication or any combination of them — and the Commonwealth can try to prove that with an officer’s observations, field testing and other evidence, not just a breath number. There is no BAC that is automatically “safe.”
If you are facing a DUI charge in Southeastern Kentucky — under any of these limits — call my office at 606-777-0000 for a free consultation to talk through your defense options.