Alabama General Knowledge CDL Practice Test

This is a free 20-question practice test for the General Knowledge portion of the Alabama 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 Alabama Law Enforcement Agency 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 Alabama.

Question 1 of 20

You are driving a 60-foot tractor-trailer at 55 mph. The minimum following distance you should maintain is:

4 seconds
5 seconds
6 seconds
7 seconds

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 2 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 3 of 20

You are driving on a two-lane road. An oncoming driver drifts into your lane. You should:

Steer right onto the shoulder
Flash your high beams
Honk your horn
Brake hard and stop in your lane

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 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

Maximum allowable steering-wheel play is approximately:

5 degrees
10 degrees
20 degrees
30 degrees

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 6 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 7 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 8 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 9 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 10 of 20

When approaching a railroad crossing, drivers of buses, school buses, and placarded hazmat vehicles must:

Speed up to clear quickly
Stop between 15 and 50 feet from the nearest rail and listen
Cross only if a train is in sight
Sound the horn

Correct. Buses, school buses, and placarded hazmat vehicles must stop at every crossing, 15 to 50 feet from the nearest rail. Look and listen, then proceed when safe.

Question 11 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 12 of 20

You are driving a 40-foot vehicle at 35 mph. The minimum following distance you should maintain is:

2 seconds
3 seconds
4 seconds
7 seconds

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 13 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 14 of 20

Wet brakes can cause:

Reduced braking power, brakes pulling to one side, or wheel lockup
Better braking
No effect on the brakes
Improved fuel economy

Correct. After driving through deep water, brakes may be wet — they can lose effectiveness, pull to one side, or grab. Apply the brakes lightly while driving slowly to dry them.

Question 15 of 20

When stopping at the scene of an accident, you should:

Move your vehicle into traffic to make room
Park well off the road, set out warning devices, and offer assistance
Leave the scene immediately
Drive around the accident

Correct. Park clear of the road, activate four-way flashers, set out warning triangles, and assist as you can without putting yourself in danger.

Question 16 of 20

When the engine is running in the cab inspection, you should check:

Oil pressure, ammeter/voltmeter, coolant temperature, engine oil temperature, and air pressure
Only the speedometer
Only the air-pressure gauge
Only the fuel gauge

Correct. After starting, watch the gauges to be sure all systems are operating normally before you drive.

Question 17 of 20

Which of these statements about backing a heavy vehicle is true?

Backing is always safe if you go slow
Whenever possible, use a helper outside the vehicle to guide you
Always back from the right side because you can see better
Backing is the same as backing a car

Correct. Backing is always risky for heavy vehicles. Use a helper, communicate with hand signals agreed in advance, back slowly, and if alone, get out and look (G.O.A.L.).

Question 18 of 20

Which of these is true about following distance for heavy vehicles?

It can be the same as a passenger car
It must be longer because heavy vehicles take longer to stop
It is irrelevant in city driving
It only matters at night

Correct. Greater weight = longer stopping distance. Use one second per 10 feet of vehicle length below 40 mph, plus an extra second above 40.

Question 19 of 20

You are about to begin a trip and notice the dashboard low-air warning is on. You should:

Drive immediately
Wait for the air pressure to build above 60 psi (warning off) and complete the air-system pre-trip
Pump the brakes
Disconnect the warning

Correct. Allow pressure to build, the warning to clear, and complete the seven-step air-brake check before driving.

Question 20 of 20

A tire may need replacement if:

Tread depth is below the minimum (4/32 steer, 2/32 other), there are sidewall cuts, exposed cord, or other damage
It looks dirty
It is over a year old
It is the wrong color

Correct. Below-minimum tread depth, sidewall damage, exposed cords, bulges, or excessive wear are all reasons to replace.

About the Alabama 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 Alabama Law Enforcement Agency 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 Alabama CDL practice tests.