14 ft
Max Height
102 in
Max Width
80,000 lb
Max Gross Weight
5
Test Questions
14.1
Papers & PermitsWhat you carry, what requires a permit
- CMVs, truck tractors, trailers, and semitrailers must carry registration papers showing the vehicle's empty weight and how much it's registered to haul.
- A load or piece of equipment that's heavier, longer, wider, or higher than the law allows needs a special permit from the Texas DMV — and won't be granted if the load could reasonably be broken down into legal-sized pieces instead.
14.2
Equipment RequirementsFlares, fire extinguishers, lighting, brakes, mud flaps
Flares, Fuses & Reflectors
Required between half an hour after sunset and half an hour before sunrise (outside city limits, or on any divided highway, anytime): at least 3 flares, 3 red electric lanterns, or 3 red emergency reflectors. When lights aren't required, 2 red flags substitute. Vehicles carrying explosives, flammable liquids/gases, or running on compressed gas can't use flame-based signals — DOT-approved triangular reflectors work instead. The first thing a disabled-vehicle driver must do is put out the proper flares, flags, or reflectors.
- Hazard lights: required immediately when a truck/bus/trailer 80+ inches wide or 30+ feet long stops on a roadway or shoulder — not required if legally parked inside city limits or stopped to load/unload passengers.
- Fire extinguisher: school buses, buses, taxis, and other for-hire passenger vehicles need at least a 1-quart chemical-type extinguisher; vehicles under Federal Motor Carrier Safety Regulations need one properly filled, mounted securely, and easily accessible.
- Reflector height: mounted 24–60 inches above the ground on pole trailers and on trucks/buses/trailers 80+ inches wide.
- Mud flaps: required behind the rear wheels on trucks/trailers with 4+ tires on the rear axle, reaching within 8 inches of the road surface.
- Slow-Moving Vehicle emblem: required on anything topping out at 25 mph or less — and it's illegal to put this emblem on anything faster.
Brake Requirements by Weight
Trailers/semitrailers/pole trailers 4,500 lbs or less: exempt from brakes. 4,500–15,000 lbs at 30 mph or under: brakes not required. 4,500–15,000 lbs over 30 mph: must have brakes on both rear-axle wheels. One control device must be able to operate all brakes in a combination.
14.3–4
Size, Weight & ExceptionsThe numbers DPS actually tests
- Height: 14 feet max, ground to top of load — it's the driver's job to confirm clearance under every bridge/overpass on the route.
- Width: 102 inches max (some exceptions — e.g., registered cotton-handling vehicles up to 120 inches, hay bales up to 144 inches).
- Length: single vehicle (non-tractor) 45 ft · semitrailer in a tractor-semitrailer combo 59 ft · semitrailer/trailer in a tractor-semitrailer-trailer combo 28.5 ft each · most other combinations 65 ft max.
- Vehicle combinations: max 3 vehicles in a combination; a vehicle under 2,500 lbs unloaded can't be coupled with more than one other vehicle.
- Gross weight: 80,000 lbs max (oversize/overweight permits available through TxDOT for certain loads).
- Overweight tolerance: if you exceed the legal limit by more than a 5% tolerance, you may have to unload down to the legal limit plus tolerance (exception: livestock, timber/pulpwood, and natural-state agricultural loads headed to first market don't have to unload).
- Load extensions: max 3 ft beyond the front, 4 ft beyond the rear without a permit. Past 4 ft rear extension, you need a red flag (at least 12" square) by day and a red light visible 500 ft by night.
- Towing connection: max 15 ft between vehicles (doesn't apply to pole trailers); a chain/rope/cable connection needs a white flag at least 12" square.
- Loose material loads (dirt, sand, gravel, etc.) must be fully enclosed or tarped to prevent spilling/blowing — natural-state agricultural products are exempt.
14.5–6
Operating Rules & Safety PracticesCoasting, following, railroad crossings, turning, backing, passing
- Coasting is illegal — never coast downgrade in neutral or with the clutch disengaged while still in gear. Downshift before starting down, not during.
- Following: leave enough space for another vehicle to safely merge into the gap between you and the vehicle ahead.
- Railroad crossings: buses, school buses, and placarded vehicles must stop at every crossing unless directed through by a signal or officer. Super-heavy equipment (crawler tractors, derricks, etc.) and explosives-carrying trucks must also always stop. Exceptions: streetcar crossings, abandoned tracks, industrial switching tracks, or signal/officer-directed crossings.
- Right turns: since a long vehicle can't hold its lane through a tight turn, approach about 4 feet from the curb, then swing wide right once your front wheels clear the corner — far enough to let the rear wheels clear the curb, without inviting someone to pass you on the right.
- Backing: walk around and check behind first, use both mirrors (you can't see the right side leaning out the left door), get a spotter if possible, and never back around a corner to turn around.
- Passing two-wheeled vehicles: leave at least 6 feet of clearance — aerodynamic pull from a large vehicle can suck a motorcycle or bicycle 2–3 feet toward you. Move fully into the next lane; don't share a lane with them.
14.7–8
Registration & Federal AdoptionWhat's exempt, what's adopted by reference
- Vehicles exempt from registration/inspection when operated temporarily: farm tractors, certain light farm trailers, implements of husbandry, power sweepers, certain golf carts.
- Texas DPS has adopted the Federal Motor Carrier Safety Regulations (49 CFR Parts 390–393, 395–397) and the Federal Hazardous Materials Regulations (Parts 171–173, 177, 178) by reference.
14.9
Sharing the RoadProfessional habits, not just rules
- Tailgating is the #1 complaint against truck drivers — keep a 4-second following gap on the open road, stretching to 6–8 seconds in bad weather.
- Speed: doubling your speed quadruples your stopping distance. Driving the speed limit saves fuel, tires, brakes — and gives you time to react.
- School buses: give them as much room as possible and expect frequent stops — the driver may be distracted by the kids on board.
- RVs and small trailers: these drivers often have less experience and are more affected by your vehicle's turbulence — slow down and give them room when passing.
Highest-Yield Facts
The numbers most likely to be tested
01
First action at a breakdown: put out flares/flags/reflectors.
02
Max height: 14 ft. Max width: 102 in.
03
Max gross weight: 80,000 lbs.
04
Reflectors required: 3 (flares, lanterns, or reflectors).
05
Hazard lights required on stop: vehicles 80+ in wide or 30+ ft long.
06
Towing connection max length: 15 ft.
07
Rear load extension over 4 ft needs a flag/light.
08
Pass two-wheeled vehicles with at least 6 ft clearance.
09
Buses, school buses & placarded vehicles must stop at every railroad crossing.
10
Coasting downgrade in neutral/clutch-out while in gear is illegal.
Test Prep — Questions & Answers
The manual's own end-of-section questions, answered in full.