Truck and trailer rules in Texas: licence classes, trailer brakes, safety chains, 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 chapters of the Texas Transportation Code, published by the Texas Legislature: chapter 521 on driver's licences, chapter 545 on rules of the road, chapter 547 on vehicle equipment and chapter 621 on vehicle size and weight. 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
Class A	Vehicle rated 26,001 pounds or more, or a combination rated 26,001 pounds or more when a towed vehicle is rated over 10,000 pounds
Class B	Vehicle rated more than 26,000 pounds, or 26,000 pounds or more towing a vehicle rated 10,000 pounds or less
Trailer brakes	Not required at 4,500 pounds gross or less; also not required from 4,501 to 15,000 pounds when drawn at not more than 30 miles per hour
Safety chains	Passenger car or light truck drawing a trailer, with listed exceptions
Width, height	102 inches wide; 14 feet high
Length	45 feet motor vehicle other than a truck-tractor; 65 feet for most combinations of up to three vehicles
Weight	20,000 pounds single axle; 34,000 pounds tandem; 80,000 pounds on a group of axles
Carrier number	Not published on the pages read

Licence classes

Section 521.081 says a Class A licence authorises a vehicle with a gross vehicle weight rating of 26,001 pounds or more, or a combination with a gross combination weight rating of 26,001 pounds or more if the rating of any vehicle in tow is more than 10,000 pounds. Section 521.082 says a Class B licence authorises a vehicle with a rating of more than 26,000 pounds, a vehicle rated 26,000 pounds or more towing a vehicle other than a farm trailer rated 10,000 pounds or less, or towing a farm trailer rated 20,000 pounds or less, and a bus seating 24 passengers or more. See chapter 521 on driver's licences.

The commercial driver licence rules sit in chapter 522, the Texas Commercial Driver's License Act. It takes its definition of a commercial motor vehicle from 49 CFR 383.5. Section 522.011 says a person may not drive a commercial motor vehicle unless the person has a commercial driver's licence from the Department of Public Safety for the class of vehicle and is not disqualified or under an out-of-service order. See chapter 522 on commercial driver's licences.

Brakes and safety chains

Section 547.401 says a trailer, semitrailer or pole trailer is not required to have brakes if its gross weight is 4,500 pounds or less, or if it is heavier than 4,500 pounds but not heavier than 15,000 pounds and is drawn at a speed of not more than 30 miles per hour. Section 547.408 sets performance numbers for a motor vehicle or combination: a braking force of 43.5 percent of gross weight for a vehicle other than a passenger vehicle, and a stop from 20 miles per hour within 40 feet for a single unit vehicle rated over 10,000 pounds, or 50 feet for other vehicles. See chapter 547 on vehicle equipment.

Section 545.410 says the operator of a passenger car or light truck may not draw a trailer, semitrailer, house trailer or another motor vehicle unless safety chains of a type the department approves are attached in the department's approved manner. The chains are defined as flexible tension members from the front of the drawn vehicle to the rear of the drawing vehicle that keep the vehicles connected if the primary connection fails. The section does not apply to an agricultural trailer or semitrailer, or to a drawn vehicle operated in compliance with the federal motor carrier safety regulations. Section 545.409 also says a chain, rope or cable connection must carry a white flag or cloth not less than 12 inches square. See chapter 545 on rules of the road.

Width, height, length and weight

Section 621.201 sets the total width of a vehicle and its load at not more than 102 inches, leaving out safety devices that the federal or state transport departments find necessary. Section 621.207 sets height at 14 feet. Section 621.203 limits a motor vehicle other than a truck-tractor to 45 feet. Section 621.205 allows a combination of not more than three vehicles, apart from truck-tractor combinations, if it is not longer than 65 feet, and says a motor vehicle with an unloaded weight under 2,500 pounds may not be coupled with more than one other vehicle or towing device. Section 621.206 says a load may not extend more than three feet past the front or, except as other law permits, more than four feet past the rear.

Section 621.101 bars a single axle weight above 20,000 pounds and a tandem axle weight above 34,000 pounds, including enforcement tolerances, and sets a formula for the gross weight of a group of axles. The gross weight on a group of two or more consecutive axles may not exceed 80,000 pounds, regardless of tire ratings, axle spacing and number of axles. A vehicle powered primarily by natural gas or electric battery may exceed its gross weight limit by up to 2,000 pounds, to a maximum of 82,000 pounds. Chapter 623 covers permits for heavier or larger loads. See chapter 621 on size and weight.