Kentucky state trucking regulations vs. federal DOT rules

Oct. 11, 2025, 7:30 p.m.
Here’s a detailed comparison of state trucking regulations in Kentucky versus the federal regulations under the Federal Motor Carrier Safety Administration (FMCSA) / United States Department of Transportation (USDOT). This will help clarify where things align, and where Kentucky has additional or different requirements.
Kentucky state trucking regulations vs. federal DOT rules

Where they overlap / align

  1. Hours of Service (HOS) for interstate carriers

    • Kentucky carriers engaged in interstate operations must follow the federal HOS rules (e.g., maximum 11 driving hours after 10 consecutive off-duty hours; 14-hour on-duty window; rest break after 8 cumulative hours of driving). 

    • These are set at the federal level, so Kentucky must enforce them for interstate operations.

  2. Requirement for USDOT number for many carriers

    • The FMCSA says: you must have a USDOT number if you operate in interstate commerce and meet certain criteria.  

    • Kentucky likewise requires carriers doing certain intrastate/ interstate business to obtain the Federal USDOT number.  

  3. Safety and driver qualification standards

    • Federal regulation sets standards for driver qualifications, medical certificates, hours, vehicle inspection and maintenance (e.g., 49 CFR Part 391 et al.).

    • Kentucky regulation (601 KAR 1:005) explicitly states that “a commercial motor vehicle and its operator … shall be governed by the … Motor Carrier Safety Regulations … adopted and issued by the United States Department of Transportation.”  

    So Kentucky incorporates (or defers to) many of the federal safety standards for carriers.

  4. Oversize/Overweight permit requirement

    • Federal rules (e.g., 23 CFR 658) set minimum width/length limits for certain segments of the national network. 

    • Kentucky has a permitting scheme for overweight/over-dimensional loads.  

    So both federal and state frameworks impose restrictions and permit regimes for large/oversize loads.

 Where Kentucky imposes additional or different requirements

  1. Medical certification for CDL drivers

    • Under federal rules, not all CDL holders may be required to hold a DOT medical certificate depending on the type of operation (see 49 CFR 391).

    • Kentucky law requires all CDL holders in the state to have a valid DOT medical card, regardless of whether they are in an excepted operation.  

    • So Kentucky is more stringent in this respect.

  2. Intrastate-only carrier licensing/authority

    • For carriers operating solely within Kentucky (intrastate), Kentucky has specific requirements: e.g., if you are a for-hire carrier operating intrastate you may need a Kentucky Intrastate For-Hire License (TC95-1 form) and other state filings.  

    • Federal interstate rules don’t cover purely intrastate operations — states fill that gap.

  3. Weight / dimension limits on state highways

    • Kentucky has weight limits for its highways (e.g., 80,000 lbs gross on many interstates, with axle‐specific limits: single axle 20,000 lbs, tandem 34,000 lbs, tridem 48,000 lbs) for state‐designated roads.  

    • Federal regulations set minimum/maximum limits for certain highways (e.g., width 102 inches on the National Network) but states retain significant authority to regulate weight/axle limits beyond those minima.  

    • Kentucky’s specific limits/routes may differ from what federal minimums allow.

  4. Oversize/Over-Dimensional Permit Requirements in Kentucky

    • Kentucky’s rules: e.g., permits for certain widths, lengths, heights; e.g., width up to 16′ allowed (with permit) in Kentucky.  

    • The federal rules (23 CFR 658) do not impose maximum height limits and allow states to set height restrictions. 

    • So Kentucky may impose more restrictive or specific state permit terms in addition to federal baseline.

  5. Fuel tax / mileage tax / intrastate filings

    • Kentucky imposes certain state‐specific taxes/licensing for vehicles operating intrastate: e.g., KYU (Kentucky highway use tax) for vehicles > 59,999 lbs (or as the literature suggests) for operation in Kentucky.  

    • Federal rules do not manage state fuel or mileage taxes — those are state functions.

 Key Points to Remember for Carriers in Kentucky

  • If you operate interstate (crossing state lines), you must comply with all applicable federal FMCSA regulations.

  • Even if you operate intrastate (within Kentucky only), you must comply with Kentucky’s state regulatory regime, which may impose additional requirements beyond federal law.

  • Having a USDOT number, operating authority, driver qualification files, electronic logs (ELDs) etc are federal requirements that will apply (depending on your operations).

  • Kentucky’s permit, weight/axle, intrastate licensing, and medical card requirements may add extra obligations — failing to comply with state rules can lead to citations even if federal rules are met.

  • When transporting oversize or overweight loads, you must check both federal minimums (for the National Network) and Kentucky’s specific permit rules, width/height/length/weight allowances.

  • Route planning should check the state’s “National Truck Network” map in Kentucky (routes designated for large trucks) and check for state‐specific truck restrictions. 

 Why This Matters

  • Non-compliance with either federal or state regulations can result in serious penalties, shutdowns, insurance issues, liability exposure.

  • Knowing where Kentucky is more restrictive helps avoid surprises (e.g., medical card requirement for all CDL holders) and ensures safe legal operation.

  • For carriers based in Kentucky, or operating frequently in Kentucky, understanding the interplay ensures you’re not treating Kentucky merely as a “follow federal law” state — there are state-specific laws.

  • For logistics/planning, the state vs federal differences influence cost (permits, taxes, fees), route choices (what roads you can use), and equipment specs (weight, size, driver qualification).