Texas CDL Knowledge Test Cheat Sheet

A condensed, skimmable recap of the rules most worth knowing cold before your exam — distilled from our full Texas practice question bank. This isn't a replacement for the Texas Driver Handbook; confirm anything time-sensitive with Texas DPS.

Getting Your CLP in Texas

As of June 1, 2026, Texas DPS tests entirely in English — knowledge exams, and the pre-trip, basic control, and road-test portions of the skills test.
Book your CLP appointment through the DPS online scheduler rather than walking in; the CLP itself stays valid for 180 days, or until your regular license expires, whichever comes first.
A DOT medical certificate is required before DPS will move your application forward, confirming you meet federal physical qualification standards.

Hours of Service

The daily limit is 11 hours of driving, but only after 10 straight hours off duty, and only within a 14-hour on-duty window that starts ticking the moment you go on duty — not just while driving.
Once you've logged 8 hours of driving since your last break, federal rule requires a 30-minute break before continuing.
Weekly caps run 60 hours over 7 days or 70 over 8, and a 34-hour continuous off-duty stretch resets the clock.
Bad weather or unexpected traffic can justify up to 2 extra hours of driving under the adverse conditions exception — but only when safety genuinely requires it.

Air Brakes

Spring brakes hold themselves released using air pressure; lose that pressure and the springs snap the brakes on automatically — a fail-safe, not a malfunction.
You'll get a low air pressure warning before the system drops below 60 psi, federally mandated so you have time to react.
Dual air brake systems exist so that losing one half still leaves you with partial braking from the other.
Air takes a moment to travel through the lines and actually apply the brakes — that lag adds real distance to your stop, plan for it.

Vehicle Inspection

Pre-trip inspections exist to catch a problem before it becomes a breakdown; post-trip inspections catch what developed during the drive, logged on a DVIR.
Steering axle tires need 4/32 inch of tread minimum — double the 2/32 inch floor for every other position on the vehicle.
A wheel with loose or missing fasteners can separate from the vehicle entirely while moving — this is a check you do every time, not just when something seems off.
Doing the inspection the same way each time is what keeps you from skipping a step out of habit.

Combination Vehicles

A combination vehicle's rear wheels track a tighter path than the front wheels through a turn — this is off-tracking, and it means you need more room than instinct suggests.
Before trusting a coupling for the trip, pull forward gently against it to confirm it's actually locked.
In a multi-trailer rig, a sharp move up front can whip the rearmost trailer far wider than your own steering input would suggest.
If a trailer disconnects or fails, the tractor protection valve cuts off that trailer's claim on your air supply, so the tractor keeps its own brakes.

Cargo Securement

The first securement check happens within 50 miles of starting; after that, recheck every 150 miles or 3 hours, whichever arrives first.
Cargo that shifts changes where the vehicle's weight sits, raising rollover risk — blocking and bracing stop movement that straps alone might not.
You can be under your overall GVWR and still have one overloaded axle, which still hurts handling and braking.

Basic Vehicle Control

A drive-wheel skid from over-acceleration gets better when you ease off the gas — hitting the brake or the throttle harder just makes it worse.
Weight doesn't stop hydroplaning; at the right speed, water builds up under the tires faster than tread can clear it, heavy vehicle or not.
Double-clutching (two separate clutch movements per gear change) syncs engine speed to the next gear on transmissions without synchronizers.
Starting uphill, hold the vehicle with the parking brake, add power, and release the brake only once you're actually moving.

Speed & Space Management

Stopping distance is really three distances stacked together — perceiving the hazard, reacting to it, and braking — and a heavier vehicle needs more of each.
Slow down before you enter a curve, not while you're in it; braking mid-curve shifts weight in a way that can trigger a skid.
Leave extra room behind a vehicle you've just passed — it may drop back into your lane sooner than you expect.

Backing & Parking

GOAL — Get Out And Look — before and during any backing maneuver, not just once at the start.
A spotter covers blind spots you physically can't see from the cab; use one when you can.
Chocks back up the parking brake on a grade; don't lean on the brake by itself.

Railroad Crossings

Certain CMVs are required to stop between 15 and 50 feet from the nearest rail.
Buses carrying passengers and HazMat-placarded vehicles stop at every crossing, posted signage or not.
Don't shift gears crossing the tracks — stalling there is one of the worst places it can happen.

HazMat Awareness

Placards need to read from all four sides of the vehicle, so anyone approaching can identify the hazard immediately.
Shipping papers describing the load must stay within the driver's reach, confirmed accurate before you leave.
A HazMat endorsement adds a TSA background check on top of the standard knowledge test.
What gets placarded and how is decided by hazard class and quantity under federal rule, not by driver judgment.

Drugs & Alcohol

Commercial drivers answer to a 0.04% BAC ceiling — exactly half the 0.08% limit that applies to non-commercial driving.
Refusing a drug or alcohol test carries the same consequences as failing one outright.
A first serious violation triggers at least a year-long federal disqualification; states can extend that floor, never shrink it.
The Clearinghouse is the federal system employers check to see a CDL holder's drug and alcohol violation history.

Medical Requirements

A medical certificate is proof you clear the federal minimum physical standards for commercial driving.
Vision and hearing standards can be met with correction — glasses, contacts, or a hearing aid all count.
Being fully honest with the medical examiner is what lets them actually verify you meet every standard, not just the obvious ones.

Vehicle Systems

A weak battery or a loose terminal can take out your lights, gauges, or ability to start — worth checking every pre-trip.
An exhaust leak can push carbon monoxide into the cab; this is a safety inspection item, not a maintenance afterthought.
Worn suspension components hurt your ability to control the vehicle, not just how smooth the ride feels.

Fire Safety

Not every extinguisher handles every fire type — an expired or undercharged one may simply fail exactly when you need it.
Popping the hood on an engine fire feeds it more oxygen; resist the instinct.

Out-of-Service Orders

An out-of-service order means an inspector found something serious enough that you can't keep operating until it's fixed.
Blow past your hours-of-service limits and you can be placed out of service on the spot until the required rest accumulates.

Accident Procedures & General Knowledge

Check for injuries and call for help first — protect the scene from further danger, like oncoming traffic, at the same time.
A crash counts as federally reportable if it involves a fatality, an injury needing immediate treatment away from the scene, or disabling damage.
Get people clear of the vehicle and off the road before you try to assess or fight a fire.
A CMV's size and limited maneuverability mean it needs more space around it to respond to a hazard than a passenger car does.
Hand-held phone use is federally banned while driving a commercial vehicle, no exceptions for the reason behind the call.
GVWR is the maximum weight the manufacturer rates the vehicle to carry — itself, cargo, passengers, and fuel included.

Last reviewed: 2026-07-14