Connecticut General Knowledge CDL Practice Test

This is a free 20-question practice test for the General Knowledge portion of the Connecticut 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 Connecticut Department of Motor Vehicles 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 Connecticut.

Question 1 of 20

If your vehicle hydroplanes, what should you do?

Brake hard immediately
Steer sharply to recover
Release the accelerator and push in the clutch
Accelerate to push through

Correct. Release the accelerator and push in the clutch. Do not brake or steer hard until the tires regain contact.

Question 2 of 20

When a vehicle ahead of you brakes hard, you should:

Brake harder
Apply the brakes immediately, even if you don't need to
Look for a way to steer around the vehicle if necessary, while preparing to brake
Honk to warn the driver behind you

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 3 of 20

When driving in heavy fog, you should:

Drive faster to get out of it
Use high-beam headlights
Pull off the road if visibility is too low to drive safely
Follow another vehicle's tail lights closely

Correct. If visibility is so poor that you cannot drive safely, pull completely off the road, turn on four-way flashers, and wait for conditions to improve.

Question 4 of 20

A "low-clearance" warning sign requires the driver to:

Verify the vehicle's height is below the posted clearance before proceeding
Ignore the sign
Sound the horn
Drive faster

Correct. Verify your vehicle's height. Hitting a low-clearance bridge or overpass is dangerous and expensive — and entirely the driver's responsibility.

Question 5 of 20

Which of the following is true about driving at night?

Headlights illuminate further than you can stop within
You should drive faster to keep up with traffic
You should drive at a speed that lets you stop within the distance illuminated by your headlights
You can rely on oncoming headlights to help you see

Correct. Drive at a speed where your stopping distance does not exceed the distance you can see — typically 250 feet on low beams, 350-500 feet on high beams.

Question 6 of 20

What is the only effective way to remove alcohol from the body?

Drinking coffee
Cold showers
Eating a heavy meal
Time

Correct. Only time eliminates alcohol from the body — at roughly one drink per hour. Coffee, food, and showers do not speed up the process.

Question 7 of 20

The most important reason for doing a vehicle inspection is to:

Comply with the law
Save fuel
Find safety problems before they cause a crash
Document mileage

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 8 of 20

Which type of fire extinguisher should you use on an electrical fire?

Class A
Class B
Class C
Class D

Correct. Class B:C dry-chemical extinguishers (often labeled "B:C" or "ABC") are appropriate for electrical fires. Never use water on an electrical fire.

Question 9 of 20

Which of these is a sign of tire failure?

Heavy thumping or vibration
A loud bang
The vehicle pulling to one side
All of the above

Correct. Vibration, a loud bang from a blowout, and pulling to one side are all classic signs of tire failure.

Question 10 of 20

What is the minimum amount of tread depth required on tires other than front (steering) tires?

1/32 inch
2/32 inch
4/32 inch
5/32 inch

Correct. Non-steer tires must have at least 2/32-inch tread depth in every major groove.

Question 11 of 20

Hazardous materials awareness is required for:

Only Hazmat-endorsed drivers
Every CDL holder, even without an H endorsement
Only owners
Only mechanics

Correct. Every CDL applicant must understand basic hazmat awareness — recognizing placards, labels, and shipping papers — even if they never haul hazmat.

Question 12 of 20

What does it mean when a driver is "hydroplaning"?

The truck is overheating
The tires lose contact with the road and ride on a film of water
The brakes have failed
The driver is dehydrated

Correct. Hydroplaning means tires have lost contact with the pavement and are riding on standing water. Steering and braking become ineffective.

Question 13 of 20

Hydroplaning is most likely to occur when:

Driving at low speed in light rain
Tires lose contact with the road and ride on water
Brakes are applied gently
Tires are over-inflated

Correct. Hydroplaning occurs when a film of water comes between the tires and the road, causing the tires to lose contact with the pavement. Higher speeds, worn tires, and standing water increase the risk.

Question 14 of 20

Which is the proper position for your hands on the steering wheel?

Both hands on the same side
One hand on top, one in your lap
Both hands firmly on opposite sides of the wheel (e.g., 9 and 3)
One hand on the wheel, one on the gear shift

Correct. Both hands should be on opposite sides of the wheel — typically the 9 o'clock and 3 o'clock positions — for steering control.

Question 15 of 20

To recover from a drive-wheel skid, you should:

Brake harder to slow down
Steer in the opposite direction of the skid
Stop accelerating, push in the clutch, and counter-steer
Apply the parking brake

Correct. Stop applying power, push in the clutch (or shift to neutral) to let the wheels turn freely, and counter-steer in the direction you want the front of the vehicle to go.

Question 16 of 20

A driver convicted of driving a CMV with a BAC of .04 or higher faces:

No penalty
A warning
Disqualification of at least one year for the first offense
License renewal

Correct. A first conviction of driving a CMV with BAC ≥ .04 disqualifies the driver for at least one year (three years if hauling hazmat).

Question 17 of 20

Doubling your speed roughly:

Doubles your stopping distance
Triples your stopping distance
Quadruples your stopping distance
Has no effect on stopping distance

Correct. Braking distance is proportional to the square of speed. Doubling speed roughly quadruples braking distance.

Question 18 of 20

When driving down a long, steep downgrade, you should:

Hold the brakes lightly the whole way down
Select the proper gear before starting down and use intermittent firm brake applications
Coast in neutral
Use only the engine brake

Correct. Select a low gear before starting down. Use the brakes in firm, intermittent applications: brake until 5 mph below safe speed, release until safe speed is regained, repeat. Continuous brake application overheats the brakes.

Question 19 of 20

When should you use four-way flashers?

Only when parked
When the vehicle is stopped or moving slowly enough to be a hazard to other traffic
Only at night
Whenever you want

Correct. Four-way emergency flashers warn other drivers when your vehicle is stopped or moving slowly relative to traffic.

Question 20 of 20

Which of the following is a good way to avoid hydroplaning?

Drive faster
Use cruise control in the rain
Slow down on wet roads, especially when standing water is visible
Over-inflate the tires

Correct. Slowing down reduces the chance of hydroplaning. Maintain proper tire inflation and tread depth, and avoid using cruise control on wet roads.

About the Connecticut 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 Connecticut Department of Motor Vehicles 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 Connecticut CDL practice tests.