Truck and trailer rules in Maryland: licence classes, trailer brakes, size and weight 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 the Maryland Transportation Article, published by the Maryland General Assembly: title 16 on licences, title 22 on vehicle equipment and title 24 on size, weight and load. 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
Commercial motor vehicle	Combination rating of 26,001 pounds or more including a towed unit rated over 10,000 pounds; or a single vehicle rated 26,001 pounds or more
Noncommercial Class B	Single vehicle or combination rated 26,001 pounds or more that is not a commercial motor vehicle
Trailer brakes	Registered gross weight over 10,000 pounds: all wheels; 3,001 to 10,000 pounds: all wheels of at least one axle, two or more axles; automatic on breakaway
Width, height	102 inches wide; 13 feet 6 inches high
Length	40 feet single unit truck; 48 feet single semitrailer; 62 feet combination with a cargo-carrying power unit
Axle weight	22,400 pounds single axle at registered gross weight of 73,000 pounds or less; 20,000 pounds above that
Safety chain	Not published on the pages read
Carrier number	Not published on the pages read

Licence classes

Section 16-803 defines a commercial motor vehicle as a motor vehicle or combination used to carry passengers or property that has a gross combination weight rating of 26,001 or more pounds including a towed unit rated over 10,000 pounds, or a gross vehicle weight rating of 26,001 or more pounds. A vehicle built for 16 or more passengers and one carrying placarded hazardous materials also count. Section 16-104.1 sets the noncommercial classes. A Class B licence covers a single vehicle or combination rated 26,001 pounds or more and any vehicle a Class C licence covers, except commercial motor vehicles, motorcycles and combinations of Class F tractor and Class G trailer vehicles. A Class C licence covers a vehicle or combination with a rating under 26,001 pounds, except commercial motor vehicles and motorcycles. A Class A licence covers combinations of Class F tractor and Class G trailer vehicles. See section 16-104.1 on licence classes.

Trailer brakes

Section 22-301 says every motor vehicle, trailer, semitrailer and pole trailer on a highway must have brakes that meet the title, and the service brakes must meet the performance requirements of section 22-302. A trailer, semitrailer or pole trailer with a registered gross weight not over 3,000 pounds need not have brakes if the weight on its wheels is not over 40 percent of the gross weight of the towing vehicle and the combination meets the performance requirements. A trailer over 3,000 and not over 10,000 pounds registered gross weight need not have brakes on all wheels if it has two or more axles and brakes on all wheels of at least one axle. A trailer with a registered gross weight over 10,000 pounds, or one with air or vacuum brakes, built after June 1, 1970, must have brakes on all wheels that apply automatically and stay applied at least 15 minutes on breakaway. A trailer over 3,000 and not over 10,000 pounds must have brakes on all wheels of at least one axle with the same breakaway rule. Subsection (l) allows surge brakes on a trailer with a rating or registered weight of 10,000 pounds or less when the combined rating is 26,000 pounds or less and other listed conditions are met. See section 22-301 on brakes.

Width, height and length

Section 24-102 says a vehicle may not be driven on a highway if its width exceeds 102 inches unless an exception applies, and the width includes any load. Section 24-104 sets the height of a vehicle and load at 13 feet 6 inches, with a 16 foot allowance for a combination carrying farm equipment. Section 24-104.1 sets lengths. A bus, single unit truck or Class M motor home may not be over 40 feet long. A single semitrailer behind a truck tractor may not exceed 48 feet, with no overall limit. A combination with a cargo-carrying power unit may not exceed 62 feet, and any other combination may not exceed 55 feet, except as the section provides. Any other vehicle may not exceed 35 feet. Section 24-105 allows a load to extend 3 feet past the front of a vehicle, with listed exceptions. See section 24-104.1 on length.

Axle weight

Section 24-108 limits the gross weight on a single axle to 22,400 pounds for a vehicle with a registered gross weight of 73,000 pounds or less, and to 20,000 pounds above 73,000 pounds. Except on interstate highways, a vehicle carrying forest products loaded in fields or other off-highway locations is allowed an axle load tolerance of 10 percent. A vehicle with a gross maximum weight over 73,000 pounds may travel only on State highways, except for a delivery or pickup by the shortest legal route. Section 24-112 lets the State Highway Administration issue oversize and overweight permits, with a fee of not less than US$30 for each oversize permit. See section 24-108 on axle and gross weight.