**603 KAR 5:066.** **Weight (mass)
limits for trucks.**

RELATES TO: KRS 189.222(10), 23 C.F.R. 658

STATUTORY AUTHORITY: KRS 174.080, 189.222, 23 C.F.R. 658

NECESSITY, FUNCTION, AND CONFORMITY: KRS 189.222(10) authorizes the Secretary of Transportation to establish reasonable weight (mass) limits for trucks using the state maintained highway system. This administrative regulation prescribes the maximum weight (mass) limits for each classification of roads in accordance with state and federal laws. These weights may only be exceeded if an overweight permit has been issued for the operation of a motor vehicle by the Transportation Cabinet.

Section 1. Highway Classifications and Truck Types. (1) Trucking highways. All state maintained roads are assigned a classification in 603 KAR 5:301. Unless the motor vehicle being operated has been issued an overdimensional permit by the Transportation Cabinet, the maximum allowable gross weight (mass) for each classification shall be as follows:

(a) Class "AAA" shall have a maximum allowable gross weight (mass) of 80,000 pounds (36,287.36 kilograms).

(b) Class "AA" shall have a maximum allowable gross weight (mass) of 62,000 pounds (28,122.70 kilograms).

(c) Class "A" shall have a maximum allowable gross weight (mass) of 44,000 pounds (20,090.05 kilograms).

(2) Truck types. For the purpose of posting bridges at the site and for listing bridge weight (mass) restrictions in this administrative regulation, the following truck types shall be used:

(a) Type 1. This shall be a single unit truck consisting of two (2) single axles.

(b) Type 2. This shall be a single unit truck consisting of one (1) steering axle and two (2) axles in tandem arrangement.

(c) Type 3. This shall be a truck consisting of one (1) steering axle and three (3) axles in tridem arrangement.

(d) Type 4. This shall be a tractor-semitrailer combination truck consisting of five (5) or more axles.

(3) Trucks with an axle combination not covered in subsection (2) of this section may be restricted by weight (mass) based on their axle spacing and weight (mass) distribution per axle in accordance with state and federal law. Information on those restrictions shall be available from the Division of Motor Carriers, Overweight and Overdimensional Permit Section.

Section 2. "AAA" Highways Except Interstates. The maximum weight (mass) limits for trucks using Class "AAA" highways, except the Interstate System, shall be as follows:

(1) Gross weight (mass), including load, shall not exceed 80,000 pounds (36,287.36 kilograms);

(2) Tire weight (force). The weight (force) transmitted to the pavement shall not exceed the product of 700 pounds (317.51 kilograms) times the aggregate width in inches (meters) established from the manufacturer's stamped tire measurement for all tires;

(3) On Class "AAA" highways if a structure or bridge has a posted load limit of less than 80,000 pounds (36,287.36 kilograms), the posted limit shall not be exceeded.

Section 3. Interstate Highways. The maximum weight (mass) limits for trucks using Class "AAA" highways which are a part of the Interstate System shall be as established in this section:

(1) Gross weight (mass), including load, shall not exceed 80,000 pounds (36,287.36 kilograms).

(2) Gross axle weight (mass) for a single axle shall not exceed 20,000 pounds (9071.84 kilograms) (with axles less than forty-two (42) inches (1.07 meters) apart to be considered as a single axle).

(3) Gross weight (mass) shall not exceed 34,000 pounds (15,422.13 kilograms) on two (2) axles in tandem arrangement which are spaced forty-two (42) inches (1.07 meters) or more apart and ninety-six (96) inches (2.44 meters) or less apart.

(4) Gross weight (mass) shall not exceed 34,000 pounds (15,422.13 kilograms) on three (3) axles in tridem arrangement if the distance between the centers of one (1) and three (3) is ninety-six (96) inches (2.44 meters) or less.

(5) Gross weight (mass) shall not exceed 48,000 pounds (21,772.42 kilograms) on three (3) axles in tridem arrangement if the distance between the centers of axles one (1) and three (3) is more than ninety-six (96) inches (2.44 meters) but less than 120 inches (3.05 meters), and the distance between any two (2) adjacent axles of the tridem is forty-two (42) inches (1.07 meters) or more, and the gross weight (mass) of the vehicle is less than or equal to 73,280 pounds (33,239.22 kilograms).

(6) The maximum gross weight (mass) allowed on two (2) consecutive sets of tandem axles shall be 34,000 pounds (15,422.13 kilograms) each, if the distance between the first and last axles of the consecutive sets of axles is thirty-six (36) feet (10.98 meters) or more.

(7) The maximum gross weight (mass) allowed on a vehicle with any other axle configuration shall be established by the bridge weight formula:

W = 500 (LN/N-1 + 12N + 36)

Where W equals gross weight, L equals distance in feet between the extreme axles of the group of consecutive axles under consideration and N equals the number of axles in the group. The load on any single axle in any arrangement shall not exceed 20,000 pounds (9071.84 kilograms) and the gross weight (mass) shall not exceed 80,000 pounds (36,287.36 kilograms). Any axle which is not included in one (1) of the combinations set forth in this subsection shall be steerable.

(8) Tire weight (force). The weight (force) transmitted to the pavement shall not exceed the product of 700 pounds (317.51 kilograms) times the aggregate width in inches (meters) established from the manufacturer's stamped tire measurement of all tires.

(9) On Class "AAA" highways which are part of the interstate system if a structure or bridge has a posted load limit of less than 80,000 pounds (36,287.36 kilograms), the posted limit shall not be exceeded.

(10) Tolerances shall not be allowed on gross weight (mass), axle weight (mass), or combinations of axle weights (mass) on vehicles operating over a Class "AAA" highway which is a part of the Interstate System.

Section 4. "AA" Highways. The maximum weight (mass) for trucks using Class "AA" highways shall be as established in this section:

(1) Gross weight (mass), including load, shall not exceed 62,000 pounds (28,122.7 kilograms).

(2) Gross axle weight (mass) for a single axle shall not exceed 20,000 pounds (9071.84 kilograms) (with axles less than forty-two (42) inches (1.07 meters) apart to be considered as a single axle).

(3) Gross weight (mass) shall not exceed 34,000 pounds (15,422.13 kilograms) on two (2) axles in tandem arrangement which are spaced forty-two (42) inches (1.07 meters) or more apart and ninety-six (96) inches (2.44 meters) or less apart.

(4) Gross weight (mass) shall not exceed 34,000 pounds (15,422.13 kilograms) on three (3) axles in tridem arrangement if the distance between the centers of axles one (1) and three (3) is ninety-six (96) inches (2.44 meters) or less.

(5) Gross weight (mass) shall not exceed 48,000 pounds (21,772.42 kilometers) on three (3) axles in tridem arrangement if the distance between axles one (1) and three (3) is more than ninety-six (96) inches (2.44 meters) but less than 120 inches (3.05 meters) apart and the distance between any two (2) adjacent axles of the tridem is forty-two (42) inches (1.07 meters) or more.

(6) Tire weight (force). The weight (force) transmitted to the pavement shall not exceed 700 pounds (317.51 kilograms) times the aggregate width in inches (meters) established from the manufacturer's stamped tire measurement of all tires.

(7) On Class "AA" highways if a structure or bridge has a posted load limit of less than 62,000 pounds (28,122.7 kilograms), the posted limit shall not be exceeded.

(8) The maximum gross weight (mass) allowed on a vehicle with any other axle configuration shall be established by the bridge weight formula:

W = 500 (LN/N-1 + 12N + 36)

Where W equals gross weight, L equals distance in feet between the extreme axles of the group of consecutive axles under consideration and N equals the number of axles in the group. The load on any single axle in any arrangement shall not exceed 20,000 pounds (9071.84 kilograms) and the gross weight (mass) shall not exceed 62,000 pounds (28,122.7 kilograms). Any axle which is not included in one (1) of the combinations set forth in this subsection shall be steerable.

Section 5. "A" Highways. The maximum weight (mass) limit for trucks using Class "A" highways shall be as established in this section:

(1) Gross weight (mass), including load, shall not exceed 44,000 pounds (20,090.05 kilograms).

(2) Gross axle weight (mass) for a single axle shall not exceed 20,000 pounds (9071.84 kilograms) (with axles less than forty-two (42) inches (1.07 meters) apart to be considered as a single axle).

(3) Gross weight shall not exceed 34,000 pounds (15,422.13 kilograms) on two (2) axles in tandem arrangement which are spaced forty-two (42) inches (1.07 meters) or more apart and ninety-six (96) inches (2.44 meters) or less apart.

(4) Tire weight (force). The weight (force) transmitted to the pavement shall not exceed the product of 700 pounds (317.51 kilograms) times the aggregate width in inches (meters) established from the manufacturer's stamped tire measurement of all tires.

(5) On Class "A" highways if a structure or bridge has a posted load limit of less than 44,000 pounds (20,090.05 kilograms), the posted limit shall not be exceeded.

(6) The maximum gross weight (mass) allowed on a vehicle with any other axle configuration shall be established by the bridge weight formula:

W = 500 (LN/N-1 + 12N + 36)

Where W equals gross weight, L equals distance in feet between the extreme axles of the group of consecutive axles under consideration and N equals the number of axles in the group. The load on any single axle in any arrangement shall not exceed 20,000 pounds (9071.84 kilograms) and the gross weight (mass) shall not exceed 44,000 pounds (20,090.05 kilograms). Any axle which is not included in one (1) of the combinations set forth in this subsection shall be steerable.

Section 6. Tolerance. There shall not be a tolerance allowed on gross weight (mass), however, a tolerance of not more than five (5) percent shall be allowed on axle weight (mass) on all state-maintained highways which are not a part of the interstate system.

Section 7. (1) As long as a highway remains a part of the state-maintained system, as established in 603 KAR 3:030, the classification of that highway in 603 KAR 5:301 shall constitute a designation by the Secretary of Transportation as contemplated by KRS 189.280.

(2) City ordinances which impose less stringent limits than this administrative regulation shall not apply to the state-maintained highways, including bridges, unless specific relinquishment of this responsibility to a city is made by the Secretary of Transportation. (2 Ky.R. 312; Am. 3 Ky.R. 3; eff. 7-7-76; 7 Ky.R. 915; eff. 7-1-81; 14 Ky.R. 272; eff. 9-10-87; 2061; eff. 7-1-88; 17 Ky.R. 2835; eff. 6-4-91; 18 Ky.R. 2370; eff. 3-7-92; 23 Ky.R. 183; eff. 9-3-96; 30 Ky.R. 1359; 2151; eff. 4-12-2004.)