Kentucky DOT Regulations for Commercial Motor Carriers

Commercial motor carriers operating in Kentucky must comply with a layered set of federal and state rules covering driver licensing, medical fitness, hours of service, vehicle weight, hazardous materials, permits, and interstate registration. The Kentucky Transportation Cabinet (KYTC) and the Kentucky State Police enforce these Kentucky DOT regulations for commercial motor carriers alongside the Federal Motor Carrier Safety Administration. Kentucky sits in the middle of the national freight network, inspection volume is high, and the penalties for getting it wrong range from fines to out-of-service orders to loss of a CDL.

Commercial Driver’s License Requirements

Kentucky issues Commercial Driver’s Licenses through the Kentucky Transportation Cabinet. You start with a Commercial Learner’s Permit, which requires a written knowledge test and a vision screening. The CLP is valid for six months, and you have to hold it for at least 14 days before taking the skills test.¹ The skills test has three parts: a pre-trip inspection, basic control maneuvers, and an on-road driving exam, all conducted in the class of vehicle you plan to drive.

CDLs come in three classes:

Class A covers combination vehicles with a gross combination weight rating of 26,001 pounds or more, where the towed unit is rated over 10,000 pounds.
Class B covers single vehicles rated at 26,001 pounds GVWR or more, or such a vehicle towing a trailer rated at 10,000 pounds or less, and also vehicles designed for 16 or more passengers if the weight threshold is met.
Class C covers vehicles under 26,001 pounds GVWR that either carry placarded hazardous materials or transport 16 or more passengers including the driver.

Endorsements are separate. Tank vehicles, passenger transport, double and triple trailers, and hazardous materials each require additional testing, and the hazmat endorsement adds a TSA security threat assessment on top of the written exam.¹

Medical Certification and Self-Certification

Every CDL holder must pass a physical examination performed by a medical examiner listed on the FMCSA’s National Registry. The medical certificate is valid for up to 24 months, though the examiner can shorten that period when a condition such as high blood pressure needs closer monitoring.² Uncontrolled diabetes, epilepsy, and severe vision impairment can disqualify a driver. Kentucky CDL holders also file a self-certification declaring whether they operate in interstate or intrastate commerce and whether their category requires a medical certificate.

Disqualifications and Serious Traffic Violations

Federal law sets mandatory disqualification periods for CDL holders. These aren’t negotiable at the state level. A first conviction for any of the offenses below results in a one-year CDL disqualification:

DUI, or a blood alcohol concentration of 0.04 or higher while operating a commercial vehicle
Refusing a required alcohol or drug test under implied consent laws
Leaving the scene of an accident
Using a commercial vehicle to commit a felony, other than a controlled substance offense
Driving on a revoked, suspended, or canceled CDL
Causing a fatality through negligent driving, including vehicular manslaughter

If the offense occurred while hauling placarded hazardous materials, the first-offense disqualification is three years. A second conviction for any combination of those offenses triggers a lifetime disqualification. Using a commercial vehicle to manufacture, distribute, or dispense controlled substances is a lifetime ban with no reinstatement.³

A separate category, “serious traffic violations,” triggers disqualification only on repeats. Two within three years mean a 60-day disqualification; three within three years mean 120 days. The federal definition covers excessive speeding, reckless driving, any traffic violation involving a fatality, operating a commercial vehicle without a valid CDL or without it in your possession, and operating without proper testing for the vehicle class or cargo type.⁴

Drug and Alcohol Clearinghouse Registration

The FMCSA’s Drug and Alcohol Clearinghouse tracks CDL holder violations related to controlled substance and alcohol testing. A single unresolved violation in the Clearinghouse will keep you off the road, regardless of what your CDL card says. Employers must query the Clearinghouse before hiring any prospective driver and must run an annual query on all current CDL-holding employees. If a limited query shows records exist, the employer has 24 hours to complete a full query (which requires the driver’s electronic consent) or move the driver out of safety-sensitive duties.⁵

Owner-operators carry a dual obligation. If you run under another carrier’s USDOT number, you register as a driver. If you operate under your own authority, you register as both driver and employer, purchase a query plan, and query yourself annually. Registration requires an FMCSA Portal account, selecting a consortium or third-party administrator for your testing program, and verifying your information in the system.⁵

Hours of Service and Electronic Logging

Federal Hours of Service rules under 49 CFR Part 395 cap how long you can drive before mandatory rest. For property-carrying drivers, the core limits are an 11-hour driving window inside a 14-hour on-duty period, both resetting only after 10 consecutive hours off duty. A 30-minute break is required after eight cumulative hours of driving. The weekly caps are 60 hours over seven consecutive days or 70 hours over eight consecutive days, with an optional 34-hour restart to reset the weekly clock.⁶

Most drivers subject to records of duty status must use an electronic logging device rather than paper logs. ELDs connect to the vehicle’s engine and record driving time automatically. Exemptions are narrow: drivers who use paper logs eight days or fewer in any 30-day period, and drivers of vehicles with engines manufactured before 2000. Kentucky officers check ELD records at weigh stations and during roadside inspections, and HOS violations are one of the most common reasons for an out-of-service order.

Weight and Axle Limits

On the Interstate System, Kentucky follows the federal cap of 80,000 pounds gross vehicle weight for five-axle combinations under 23 U.S.C. § 127, with a 20,000-pound single-axle limit and a 34,000-pound tandem-axle limit.⁷ The Federal Bridge Formula governs how weight must be distributed across axle groups based on axle spacing.

Off the interstate, Kentucky Revised Statutes 189.221 and 189.222 use a tiered system based on how the Transportation Cabinet Secretary classifies the road:⁸

Class AAA highways: up to 80,000 pounds gross, no axle weight limit under that gross.
Class AA highways: 62,000 pounds gross.
Class A highways: 44,000 pounds gross.
All other highways: 36,000 pounds gross.

Non-interstate highways allow a 5 percent tolerance per axle load for vehicles under 80,000 pounds gross.⁹ Seasonal weight restrictions apply on certain roads during winter and spring thaw periods. Even when your gross weight is legal, exceeding an individual axle limit can still bring a fine, so load distribution matters as much as the total.

Overweight Fines

Kentucky calculates overweight fines at two cents per pound of excess. When the excess is more than 5,000 pounds, the rate is still two cents per pound, with a $100 floor and $500 ceiling. Violating a posted weight limit on a state-maintained bridge more than 75 years old carries steeper penalties: $500 for a first offense, $1,000 for a second within one year, and $2,000 for any subsequent offense within a year. Exceeding a permit’s weight allowance while on the permitted route is a $100 fine; running off the permitted route puts you back under the standard per-pound penalties.

Oversize and Overweight Permits

The basic dimension limits on non-designated Kentucky highways are 11.5 feet in height, 96 inches (8 feet) in width, 26.5 feet in length for single trucks, and 30 feet for semitrailers.⁸ Designated highways allow larger dimensions set by the Transportation Cabinet Secretary. Anything exceeding the applicable limit needs a special permit from the Division of Motor Carriers under KRS 189.270. Even with a permit, no load can exceed 16 feet wide, 120 feet long, or 160,000 pounds.¹⁰

Single-trip permits cost $60 and are tied to one vehicle, route, and load. A 4 percent service fee applies for credit card payments, or $3 for ACH.¹¹ Annual permits vary by operation:

Non-divisible loads under 14 feet wide: $250
Non-divisible loads 14 to 16 feet wide: $500
Farm loads under 14 feet wide: $80
Farm loads 14 to 16 feet wide: $150
Metal commodities: $1,250
Non-divisible steel (statewide): $500
Annual feed certificate: $150
Manufactured homes: $1,500

All permits are route-specific.¹²

Escort Vehicles

Oversize loads that exceed width or length thresholds must travel with escort vehicles, and the requirements depend on whether you’re on a multi-lane or two-lane road. On multi-lane highways, one rear escort is required past 12 feet wide, one front and one rear past 14 feet, and two front and two rear past 16 feet. For length on multi-lane roads, one rear escort is required past 110 feet, and one front plus two rear past 120 feet. On two-lane highways the width thresholds trigger sooner: one front and one rear past 12 feet, and two front and two rear past 16 feet. For length on two-lane roads, one front escort past 75 feet, adding a rear past 85 feet, and two rear past 120 feet. Escort rules are conditions of the permit itself.¹³

Hazardous Materials Transport

Hauling hazardous materials in Kentucky means complying with both the federal Hazardous Materials Regulations administered by the Pipeline and Hazardous Materials Safety Administration and the Kentucky hazmat statutes at KRS 174.400 through 174.425, which the legislature enacted because of the state’s central role in national freight movement.¹⁴

The driver needs a Hazardous Materials Endorsement on the CDL, which requires the written knowledge test and a TSA security threat assessment. The carrier must register with the state before transporting hazardous materials, provide proof of liability insurance, and confirm familiarity with the applicable USDOT safety regulations.¹⁵

Federal placarding rules under 49 CFR Part 172 require the correct placards identifying the hazard class, and shipping papers describing the materials must be accessible to the driver at all times and to emergency responders in an incident.¹⁶ Some hazardous materials face route restrictions barring travel through tunnels, densely populated areas, or other sensitive zones without a special permit. Placarding, labeling, or routing violations can trigger out-of-service orders and significant federal penalties.

Interstate Authority: UCR and IFTA

Unified Carrier Registration

Every for-hire carrier, private carrier, broker, freight forwarder, and leasing company running in interstate or international commerce has to register annually through UCR. Intrastate-only carriers are exempt. Fees are based on fleet size (power units only, not trailers) and run from $46 for the smallest operators up to $44,836 for the largest fleets. Brokers and leasing companies pay the minimum bracket fee regardless of size. The 2026 registration year opened October 1, 2025, with enforcement starting January 1, 2026.¹⁷ You don’t have to carry a UCR credential in the vehicle; officers verify registration electronically.

International Fuel Tax Agreement

IFTA simplifies fuel tax reporting for carriers operating in two or more member jurisdictions. You need an IFTA license and decals if your base jurisdiction is a member and you run qualified motor vehicles across state or provincial lines. A qualified motor vehicle has two axles and a gross weight over 26,000 pounds, three or more axles regardless of weight, or a combination exceeding 26,000 pounds.¹⁸ Your base jurisdiction issues one license (copied and placed in each vehicle) and two decals per vehicle. Carriers that only occasionally cross state lines can buy trip permits instead.

Roadside Inspections and Correcting Errors

The Commercial Vehicle Enforcement division within the Kentucky State Police conducts inspections following the North American Standard Inspection Program developed by the Commercial Vehicle Safety Alliance. Inspections happen at fixed weigh stations, portable inspection sites, or during traffic stops.

On the vehicle, inspectors check brake systems, tires, lights, steering components, and cargo securement under 49 CFR Part 393.¹⁹ Defects serious enough to pose a safety risk put the vehicle out of service until repairs are done. On the driver side, officers check the CDL, medical certificate, ELD records, and hours-of-service compliance. HOS problems are among the most frequent triggers for an out-of-service order.

Challenging an Inspection Report Through DataQs

If an inspection report contains information you believe is inaccurate, the FMCSA’s DataQs system lets you file a Request for Data Review. This matters because inspection violations flow into your carrier safety scores under the Compliance, Safety, and Accountability program, and those scores affect how often your vehicles get pulled in. If a citation was dismissed or changed in court, you can submit certified court documentation through DataQs and ask for a correction.²⁰ There is no published deadline for submitting a review request, but the sooner bad data comes off your record, the less it costs you in future inspection frequency.

1
drive.ky.gov. Commercial Driver’s License Manual
2
Federal Motor Carrier Safety Administration (FMCSA). DOT Medical Exam and Commercial Motor Vehicle Certification
3
GovInfo. 49 CFR Part 383 Subpart D – Driver Disqualifications and Penalties
4
LII / Legal Information Institute. 49 USC 31301(13) – Definition: Serious Traffic Violation
5
FMCSA. Drug and Alcohol Clearinghouse Registration and Requirements for Owner-Operators
6
eCFR. 49 CFR Part 395 – Hours of Service of Drivers
7
Office of the Law Revision Counsel. 23 USC 127 – Vehicle Weight Limitations-Interstate System
8
Justia. Kentucky Revised Statutes 189.221 – Basic Height, Width, Length, and Weight Limits for Trucks, Trailers, Manufactured Homes, or Vehicles – Exception
9
FHWA Freight Management and Operations. Compilation of Existing State Truck Size and Weight Limit Laws – Appendix A
10
Justia. Kentucky Revised Statutes 189.270 – Special Permits to Exceed Limits – Administrative Regulations
11
Kentucky Transportation Cabinet. Frequently Asked Questions – Overweight Over-Dimensional
12
Kentucky Transportation Cabinet. Overweight-Over-Dimensional Permits
13
Kentucky Transportation Cabinet. Escort Requirements – Overweight Over-Dimensional
14
Kentucky Legislative Research Commission. Kentucky Revised Statutes 174.400 – Legislative Intent
15
Kentucky Legislative Research Commission. 601 KAR 40:020 – Application for License to Operate Vehicles Transporting Municipal Solid Waste
16
eCFR. 49 CFR Part 172 Subpart F – Placarding
17
UCR Plan. Fee Brackets
18
IFTA, Inc. Carrier Information
19
eCFR. 49 CFR Part 393 – Parts and Accessories Necessary for Safe Operation
20
Federal Motor Carrier Safety Administration. Correcting a Motor Carrier’s Safety Data (DataQs)