Truck and trailer rules in Arizona: licence classes, trailer brakes and size limits

This page reports what the official source says. It is not legal advice: ask the office named here. All of the sources are sections of Title 28 of the Arizona Revised Statutes, published on the Arizona Legislature website. Federal background and the other places are on the parent page, trucks and trailers for tree work.

At a glance

Item	What the sources say
Licence line	Class D covers a single vehicle rated 26,000 pounds or less; class B starts at a rating of 26,001 pounds; class A covers a combination of 26,001 pounds or more that tows a unit rated over 10,000 pounds
Trailer brake weight	Brakes on a trailer or semitrailer with a gross weight of 3,000 pounds or more, with automatic application if the trailer breaks away
Width	8 feet; 102 inches on interstate highways and designated routes
Height	13 feet 6 inches; 14 feet on designated routes
Length	40 feet for a vehicle; 28 feet 6 inches for a trailer behind a truck; 65 feet for a truck and semitrailer
Axle weights	20,000 pounds on one axle; 34,000 pounds on a tandem; 80,000 pounds on a combination of five axles or more
Carrier number	Not published on the pages read

Licence classes

Section 28-3101 sets the driver licence classes. Class A is valid for a motor vehicle that tows a vehicle with a gross vehicle weight rating of more than 10,000 pounds when the combined rating is 26,001 pounds or more, and for anything that needs class B, C or D. Class B is valid for a single motor vehicle rated 26,001 pounds or more, and for such a vehicle towing a unit rated 10,000 pounds or less. Class C and class D are each valid for a single vehicle rated 26,000 pounds or less, towing a unit of 10,000 pounds or less, or towing a heavier unit as long as the combined rating stays under 26,001 pounds. Class C also covers vehicles that must be placarded for hazardous materials and buses. Section 28-3001 defines a commercial motor vehicle with the same 26,001 pound line, counting a towed unit rated over 10,000 pounds, and separately names a bus and a vehicle that must be placarded. See section 28-3101 on licence classes and section 28-3001 on definitions.

Trailer brakes

Section 28-952 says a trailer or semitrailer with a gross weight of 3,000 pounds or more, operated on a highway, must have brakes adequate to control, stop and hold the vehicle. The brakes must be designed to be applied by the driver of the towing vehicle from the cab, or to work automatically when the service brakes of the towing vehicle are applied. The section adds that the brakes must be designed and connected so that they apply automatically if the towed vehicle accidentally breaks away. For a new trailer sold in the state, service brakes on all wheels are required, except that a trailer with a gross weight of less than 3,000 pounds need not have brakes. A vehicle sold in the state after July 1, 1964 needs parking brakes that hold on any grade where it is operated. The pages read do not mention safety chains. See section 28-952 on required brake equipment.

Width, height and length

Section 28-1093 says the total outside width of a vehicle or its load may not exceed 8 feet. A vehicle may be up to 102 inches wide, not counting safety equipment, on any part of the interstate system, any other qualifying federal aid highway, a state highway the director designates, streets a local authority designates, and a highway that reasonably gets to those routes from terminals and facilities that provide food, fuel, repairs and lodging. See section 28-1093 on vehicle width.

Section 28-1094 sets the height at 13 feet 6 inches above the level surface, unladen or with a load, and lets the state and local authorities designate routes for 14 feet without a permit. The section also lets the department issue a one year permit for a laden height up to 14 feet on designated routes, with a fee of US$45 for each motor vehicle covered. See section 28-1094 on vehicle height.

Section 28-1095 sets 40 feet as the extreme overall length of a vehicle with its load, including bumpers, and exempts a semitrailer used with a truck or truck tractor. A combination may not consist of more than two units, except that a truck or truck tractor and semitrailer may draw one trailer or a forklift. The trailer in a truck and trailer combination may not exceed 28 feet 6 inches, and a truck and semitrailer combination may not exceed an overall length of 65 feet. See section 28-1095 on vehicle length.

Weight and special permits

Section 28-1100 sets the maximum gross weights on all highways: 20,000 pounds on one axle, 34,000 pounds on a tandem axle, and 80,000 pounds on a combination of five axles or more, with a formula for groups of axles. It also says that being registered for a declared gross weight above the legal limit is not a defense to an overweight charge. Section 28-1103 lets the director, and a local authority on its own roads, issue a written special permit on written application and for good cause for a vehicle or load over the size or weight maximums. The director adopts rules for overdimensional and overweight loads and may set fees to cover the review. See section 28-1100 on gross weight and section 28-1103 on special permits.