(a) It shall be unlawful for any person to drive or move on any highway in this state any vehicle or vehicles of a size or weight except in accordance with the following:
(1) WIDTH. Vehicles and combinations of vehicles, operating on highways with traffic lanes 12 feet or more in width, shall not exceed a total outside width, including any load thereon, of 102 inches, exclusive of mirrors or other safety devices approved by the Department of Transportation. The Director of Transportation may, in his or her discretion, designate other public highways for use by vehicles and loads with total outside widths not exceeding 102 inches, otherwise; vehicles and combinations of vehicles, operating on highways with traffic lanes less than 12 feet in width, shall not exceed a total outside width, including any load thereon, of 96 inches, exclusive of mirrors or other safety devices approved by the Department of Transportation. No passenger vehicle shall carry any load extending beyond the line of the fenders. No vehicle hauling forest products or culvert pipe on any highway in this state shall have a load exceeding 102 inches in width.
(2) HEIGHT. No vehicle or semitrailer or trailer shall exceed in height 13 1/2 feet, including load.
(3) LENGTH. No vehicle shall exceed in length 40 feet; except, that the length of a truck-semitrailer combination, semitrailers, including load, used in a truck tractor-semitrailer combination, shall not exceed 57 feet; semitrailers and trailers, including load, used in a truck tractor-semitrailer-trailer combination, shall not exceed 28 1/2 feet each; and motor vehicles designed, used, or maintained primarily as a mobile dwelling, office, or commercial space, commonly called motor homes, shall not exceed 45 feet. Semitrailers exceeding 53 1/2 feet shall only be operated on highways designated pursuant to Section 32-9-1 and shall only be operated when the distance between the kingpin of the semitrailer and the rearmost axle or a point midway between the two rear axles, if the two rear axles are tandem axles, does not exceed 41 feet and if the semitrailer is equipped with a rear underride guard of a substantial construction consisting of a continuous lateral beam extending to within four inches of the lateral extremities of the semitrailer and located not more than 22 inches from the surface as measured with the semitrailers empty and on a level surface. For purposes of enforcement of this subdivision, lengths of semitrailers and trailers refer to the cargo carrying portion of the unit. Truck tractor units used exclusively in combinations transporting motor vehicles may directly carry a portion of the cargo, provided that the combinations are restricted to truck tractor-semitrailer combinations only and provided further that the overall length of these particular combinations shall not exceed 65 feet; except that the overall length of stinger-steered type units shall not exceed 80 feet. No truck tractor-semitrailer combination used exclusively for transporting motor vehicles shall carry any load extending more than four feet beyond the front or six feet beyond the rear of the combination. No other vehicle operated on a highway shall carry any load extending more than a total of five feet beyond both the front and rear, inclusive, of the vehicle.
(4) WEIGHT.
a. The gross weight imposed on the highway by the wheels of any one axle of a vehicle shall not exceed 20,000 pounds, or such other weight, if any, as may be permitted by federal law to keep the state from losing federal funds; provided, that inadequate bridges shall be posted to define load limits.
b. For the purpose of this section, an axle load shall be defined as the total load transmitted to the road by all wheels whose centers are included between two parallel transverse vertical planes 40 inches apart, extending across the full width of the vehicle.
c. Subject to the limit upon the weight imposed upon the highway through any one axle as set forth herein, the total weight with load imposed upon the highway by all the axles of a vehicle or combination of vehicles shall not exceed the gross weight given for the respective distances between the first and last axle of the vehicle or combination of vehicles, measured longitudinally to the nearest foot as set forth in the following table:
| COMPUTED GROSS WEIGHT TABLE | |
| For various spacings of axle groupings |
| Distance in feet between first and last axles of vehicle or combination of vehicles | Maximum load in pounds on all the axles |
| 2 axles | 3 axles | 4 axles | 5 axles | 6 axles | |
| 8 or less | 36,000 | 42,000 | 42,000 | ||
| 9 | 38,000 | 42,500 | 42,500 | ||
| 10 | 40,000 | 43,500 | 43,500 | ||
| 11 | 44,000 | 44,000 | |||
| 12 | 45,000 | 50,000 | 50,000 | ||
| 13 | 45,500 | 50,500 | 50,500 | ||
| 14 | 46,500 | 51,500 | 51,500 | ||
| 15 | 47,000 | 52,000 | 52,000 | ||
| 16 | 48,000 | 52,500 | 58,000 | 58,000 | |
| 17 | 48,500 | 53,500 | 58,500 | 58,500 | |
| 18 | 49,500 | 54,000 | 59,000 | 59,000 | |
| 19 | 50,000 | 54,500 | 60,000 | 60,000 | |
| 20 | 51,000 | 55,500 | 60,500 | 66,000 | |
| 21 | 51,500 | 56,000 | 61,000 | 66,500 | |
| 22 | 52,500 | 56,500 | 61,500 | 67,000 | |
| 23 | 53,000 | 57,500 | 62,500 | 68,000 | |
| 24 | 54,000 | 58,000 | 63,000 | 68,500 | |
| 25 | 54,500 | 58,500 | 63,500 | 69,000 | |
| 26 | 56,000 | 59,500 | 64,000 | 69,500 | |
| 27 | 57,000 | 60,000 | 65,000 | 70,000 | |
| 28 | 59,000 | 60,500 | 65,500 | 71,000 | |
| 29 | 60,000 | 61,500 | 66,000 | 71,500 | |
| 30 | 62,000 | 66,500 | 72,000 | ||
| 31 | 63,500 | 67,000 | 72,500 | ||
| 32 | 64,500 | 68,000 | 73,500 | ||
| 33 | 65,000 | 69,000 | 74,000 | ||
| 34 | 65,500 | 70,000 | 74,500 | ||
| 35 | 66,500 | 71,000 | 75,000 | ||
| 36 | 67,000 | 72,000 | 76,000 | ||
| 37 | 68,000 | 73,000 | 77,000 | ||
| 38 | 69,000 | 74,000 | 78,000 | ||
| 39 | 70,000 | 75,000 | 79,000 | ||
| 40 | 71,000 | 76,000 | 80,000 | ||
| 41 | 72,000 | 77,000 | 81,000 | ||
| 42 | 73,000 | 78,000 | 82,000 | ||
| 43 | 74,000 | 79,000 | 83,000 | ||
| 44 and over | 75,000 | 80,000 | 84,000 |
Except as provided by special permits, no vehicle or combination of vehicles exceeding the gross weights specified above shall be permitted to travel on the public highways within the State of Alabama.
No vehicle or combination of vehicles shall be permitted to operate on any portion of the Interstate Highway System of Alabama that shall have a greater weight than 20,000 pounds carried on any one axle, including all enforcement tolerances, or with a tandem axle weight in excess of 34,000 pounds, including all enforcement tolerances, or with an overall gross weight on a group of two or more consecutive axles produced by application of the following formula:
| W=500 | (LN | + | 12N | + | 36) | |
| (N-1) |
d. For purposes of enforcement of this subdivision, all weights less than or equal to the sum of the weight otherwise prescribed by this subdivision, plus an additional weight to be calculated by multiplying the weight prescribed by this subdivision by one-tenth (.10) that shall represent a scale or enforcement tolerance, shall be deemed to be in compliance with the requirements of this section, and shall not constitute violations thereof. No evidence shall be admitted into evidence or considered by the trier of fact in any civil action unless the evidence proffered would tend to prove that the weight of the vehicle exceeded the amount provided in this subsection. Nothing in this paragraph d. shall restrict or affect the right of any defendant to place in evidence such evidence tending to prove the defendant was in compliance with this section.
e. Dump trucks, dump trailers, concrete mixing trucks, fuel oil, gasoline trucks, and trucks designated and constructed for special type work or use shall not be made to conform to the axle spacing requirements of paragraph (4)c of this section; provided, that the vehicle shall be limited to a weight of 20,000 pounds per axle plus scale tolerances; and, provided further, that the maximum gross weight of the vehicles shall not exceed the maximum weight allowed by this section for the appropriate number of axles, irrespective of the distance between axles, plus allowable scale tolerances. All axles shall be brake equipped. Trucks delivering asphalt plant mix which do not exceed the maximum allowable gross weight and operate within 50 miles of their home base shall not be required to conform to the requirements of paragraph (4)a of this section. Concrete mixing trucks which operate within 50 miles of their home base and do not exceed the maximum allowable gross weight shall not be required to conform to the requirements of paragraph (4)a of this section. It shall be a violation if the vehicles named under this subdivision travel upon bridges designated and posted by the Transportation Director as incapable of carrying the load.
f. If the driver of any vehicle can comply with the weight requirements of this section by shifting or equalizing the load on all wheels or axles and does so when requested by the proper authority, the driver shall not be held to be operating in violation of this section.
g. When portable scales are used in the enforcement of this section, the axles of any vehicle described or commonly referred to as tandem or triaxle rigs or units (that is, vehicles having two or more axles in addition to a steering axle), the group of tandem or triaxles shall be weighed simultaneously, and the total weight so derived shall be divided by the number of axles weighed in the group to arrive at the per axle weight, except that if any one axle in the group exceeds 20,000 pounds in weight, it shall not exceed the weight of any other axle in the group by more than 50 percent. When portable scales are used to determine the weight of a vehicle pursuant to this section, the operator of the vehicle will be permitted to move the vehicle to the nearest platform scales certified by the Department of Agriculture and Industries and operated by a bonded operator within a distance of 10 highway miles, accompanied by an enforcement officer to verify the accuracy of the portable scales used in determining the vehicle weight. If the weight of the vehicle is shown by the platform scales to be within the legal limits of this section, the operator of the vehicle shall not be held to be in violation of this section.
h. The governing body of a county, by appropriate resolution, may authorize limitations less than those prescribed herein for vehicles operated upon the county highways of the county.
i. The Department of Transportation may post or limit any road or bridge to weights less than those prescribed by this section. It is the legislative intent and purpose that this section be rigidly enforced by the Department of Transportation, the Alabama State Law Enforcement Agency and any other authorized law enforcement officers of the state, any county, or city and incorporated towns.
j. Two and three axle vehicles being used exclusively for the purpose of transporting agricultural commodities or products to and from a farm and for agricultural purposes relating to the operation and maintenance of a farm by any farmer, custom harvester or husbandman may not be made to conform to the axle requirements of paragraph (4)a of this section or the gross weight requirements of paragraph (4)c of this section.
(b)(1) Any vehicle utilizing an auxiliary power or idle reduction technology unit in order to promote reduction of fuel use and emissions because of engine idling shall be allowed an additional 400 pounds total to the gross, axle, tandem, or bridge formula weight limits defined in this section.
(2) To be eligible for the exception provided in this subsection, the operator of the vehicle must provide written proof or certification of the weight of the auxiliary power unit (APU) and demonstrate or certify the idle reduction technology is fully functional at all times.
(3) Written proof or certification of the weight of the APU must be available to law enforcement officers if the vehicle is found in violation of applicable weight laws. The weight allowed cannot exceed 400 pounds or the actual weight proven or certified, whichever is less.
(4) It is the intent of this subsection to apply at the state highway level the weight limit increase for vehicles using a functioning auxiliary power or idle reduction technology as provided in the Federal Energy Policy Act of 2005.
(c)(1) Any motor vehicle, if operated by an engine fueled primarily by natural gas, may exceed any vehicle weight limit, up to a maximum gross vehicle weight of 82,000 pounds, under this section by an amount that is equal to the difference between:
a. The weight of the vehicle attributable to the natural gas tank and fueling system carried by that vehicle; and
b. The weight of a comparable diesel tank and fueling system.
(2) This subsection applies on federal interstate highways to the weight limit increases for vehicles using an EPA certified natural gas engine or an EPA approved conversion unit installed on the vehicle which allows the vehicle to operate primarily on compressed natural gas or liquefied natural gas.
Last modified: May 3, 2021