Question 1 of 20
When you double your speed from 20 to 40 mph, the impact in a crash is:
Correct. Crash energy is proportional to the square of speed. Doubling speed quadruples the energy of impact.
Utah General Knowledge CDL Practice Test
This is a free 20-question practice test for the General Knowledge portion of the Utah Commercial Driver's License knowledge exam. Questions are pulled from a pool of 97 drawn from the AAMVA CDL Manual, which is the source document the Utah Driver License Division uses to write its actual exam.
How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Utah.
Question 2 of 20
If your vehicle hydroplanes, what should you do?
Correct. Release the accelerator and push in the clutch. Do not brake or steer hard until the tires regain contact.
Question 3 of 20
The most important reason for doing a vehicle inspection is to:
Correct. A pre-trip inspection is meant to find problems that could cause a crash or breakdown. Compliance is a side effect, not the purpose.
Question 4 of 20
You are about to begin a trip and notice the dashboard low-air warning is on. You should:
Correct. Allow pressure to build, the warning to clear, and complete the seven-step air-brake check before driving.
Question 5 of 20
You are driving on a two-lane road. An oncoming driver drifts into your lane. You should:
Correct. When an oncoming driver drifts into your lane, the safer escape is right onto the shoulder. Steering left risks a head-on if the other driver corrects.
Question 6 of 20
How many red reflective triangles must you carry in your commercial vehicle for emergency warning?
Correct. You must carry three red reflective triangles, six fusees, or three liquid-burning flares for emergency warning use.
Question 7 of 20
When the engine is running in the cab inspection, you should check:
Correct. After starting, watch the gauges to be sure all systems are operating normally before you drive.
Question 8 of 20
When a vehicle ahead of you brakes hard, you should:
Correct. Plan your escape: identify a clear lane or shoulder. If you can steer to safety, you save reaction time. If not, brake firmly without locking the wheels.
Question 9 of 20
How often must drivers inspect their cargo and securing devices?
Correct. Federal rule: inspect within the first 50 miles, then every 150 miles or 3 hours of driving, whichever comes first, plus every change of duty status.
Question 10 of 20
A driver-side skid can cause a tractor-trailer to:
Correct. When the drive wheels lose traction and the trailer continues forward, the tractor pivots and the rig jackknifes.
Question 11 of 20
You are driving a 60-foot tractor-trailer at 55 mph. The minimum following distance you should maintain is:
Correct. Above 40 mph, add one extra second to the per-10-foot rule. A 60-foot vehicle = 6 seconds + 1 = 7 seconds at 55 mph.
Question 12 of 20
The blood-alcohol concentration (BAC) at or above which a CDL driver is considered to be driving under the influence in a commercial motor vehicle is:
Correct. The federal BAC limit for CDL drivers operating a commercial vehicle is .04 — half the .08 limit for non-commercial drivers in most states.
Question 13 of 20
Which of these is true about driving in fog?
Correct. In fog, high beams reflect off water particles and impair vision. Use low beams. Many drivers also use four-way flashers when moving slowly to alert traffic.
Question 14 of 20
A driver who has been disqualified is:
Correct. A disqualified driver may not operate a commercial motor vehicle on public roads, regardless of supervision.
Question 15 of 20
Maximum allowable steering-wheel play is approximately:
Correct. Steering wheel play should not exceed 10 degrees (roughly 2 inches on a 20-inch wheel). More than that, the vehicle is hard to steer.
Question 16 of 20
You are driving a 40-foot vehicle at 35 mph. The minimum following distance you should maintain is:
Correct. The rule of thumb: 1 second per 10 feet of vehicle length below 40 mph. A 40-foot vehicle therefore needs 4 seconds of following distance.
Question 17 of 20
A "convex mirror" on the side of a tractor:
Correct. Convex (curved) mirrors widen the field of view but distort distance perception — objects look smaller and farther than they actually are.
Question 18 of 20
Which of the following is NOT part of the seven-step pre-trip inspection method?
Correct. The radio is not part of the safety inspection. The seven-step method covers approach, engine compartment, in-cab checks, lights, walk-around, signal lights, and brake checks.
Question 19 of 20
What is "black ice"?
Correct. Black ice is a thin, clear sheet of ice that looks like wet pavement. Suspect it whenever the temperature is at or below freezing and the road appears wet.
Question 20 of 20
Which of the following can cause the wheels of your vehicle to skid on a curve?
Correct. Posted curve advisory speeds assume cars; a heavy commercial vehicle with a high center of gravity may roll over or skid even at the posted speed. Slow before the curve, accelerate gently through it.
About the Utah General Knowledge exam
Most state DMVs administer 50 General Knowledge questions and require 80% (40 correct) to pass. Questions are pulled from a much larger pool, so two applicants taking the test on the same day will see different mixes. The questions on this site are drawn from the AAMVA CDL Manual chapters that every state's exam is built from.
The Utah Driver License Division follows the federal CDL standards established by FMCSA. To earn the General Knowledge credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.
Want more practice? Try the full General Knowledge question bank or browse all Utah CDL practice tests.