Take CDL Practice Questions - Commercial Driver's License (General Knowledge) Exam

QUESTION 1 / 25

What is the first step in the seven-step pre-trip inspection method?

Choose one answer below.

AApproach the vehicle and check its general condition✓BCheck under the hood✓CStart the engine and inspect inside the cab✓DWalk around and inspect the entire vehicle✓

QUESTION 2 / 25

During a pre-trip inspection, what should you check in the engine compartment?

Choose one answer below.

AOnly the oil level✓BOil level, coolant level, power steering fluid, belts, and hoses✓COnly the coolant level and belts✓DOnly items visible without opening any caps✓

QUESTION 3 / 25

When performing a pre-trip inspection, the driver should ensure that the steering wheel free play (lash) does not exceed what limit?

Choose one answer below.

A5 degrees in either direction✓B10 degrees in either direction (approximately 2 inches on a 20-inch wheel)✓C15 degrees in either direction✓D20 degrees in either direction✓

QUESTION 4 / 25

During the cab check portion of a pre-trip inspection, you should test the parking brake by:

Choose one answer below.

ADriving forward slowly and applying the parking brake✓BPutting the vehicle in gear with the parking brake set and gently pressing the accelerator to see if the vehicle holds✓CVisually checking that the parking brake handle is in the correct position✓DChecking the parking brake cable under the vehicle✓

QUESTION 5 / 25

Which emergency equipment is required to be on a commercial motor vehicle?

Choose one answer below.

AFire extinguisher, spare fuses, and three red reflective triangles✓BFirst aid kit, fire extinguisher, and flares only✓CFire extinguisher and road flares only✓DSpare tire, jack, and reflective vest✓

QUESTION 6 / 25

A post-trip inspection report is important because:

Choose one answer below.

AIt is only required for vehicles carrying hazardous materials✓BIt alerts the carrier to vehicle defects that may need repair before the vehicle is driven again✓CIt replaces the need for the next driver to do a pre-trip inspection✓DIt is optional but recommended by the FMCSA✓

QUESTION 7 / 25

During a pre-trip inspection, the driver notices a coolant leak near the water pump. What should the driver do?

Choose one answer below.

ANote it on the report and drive carefully to the next service stop✓BAdd more coolant and continue the trip✓CDo not drive the vehicle until the leak is repaired✓DDrive only short distances and monitor the temperature gauge✓

QUESTION 8 / 25

Which of the following is an out-of-service condition that would prevent a vehicle from being driven?

Choose one answer below.

AA small crack in the windshield that does not obstruct the driver's view✓BA missing mud flap on a rear wheel✓CBrake lining thickness below the minimum allowed by regulations✓DA broken antenna on the CB radio✓

QUESTION 9 / 25

During the pre-trip inspection, which of the following should a driver check regarding the exhaust system?

Choose one answer below.

AOnly that the muffler is present✓BThat the exhaust system is secure, not leaking, and not in contact with fuel lines, wiring, or air lines✓COnly that exhaust fumes are not entering the cab✓DThat the catalytic converter is functioning properly by checking emissions color✓

QUESTION 10 / 25

What is the minimum tread depth required for steer axle tires on a commercial motor vehicle?

Choose one answer below.

A2/32 of an inch✓B4/32 of an inch✓C6/32 of an inch✓D1/32 of an inch✓

QUESTION 11 / 25

What is the minimum tread depth required for tires on drive and trailer axle positions?

Choose one answer below.

A4/32 of an inch✓B2/32 of an inch✓C6/32 of an inch✓D1/32 of an inch✓

QUESTION 12 / 25

When inspecting slack adjusters on an S-cam brake system, the pushrod stroke at the brake chamber should not exceed what general limit?

Choose one answer below.

A1/2 inch✓B1 inch✓CThe adjustment limit varies by chamber size, but generally should not exceed about 2 inches✓D4 inches✓

QUESTION 13 / 25

During a tire inspection, you notice a bulge on the sidewall of one of the steer tires. What should you do?

Choose one answer below.

AContinue driving but avoid high speeds✓BHave the tire replaced before driving the vehicle✓CRotate the tire to a non-steer position✓DReduce air pressure to alleviate the bulge✓

QUESTION 14 / 25

What is the purpose of the brake drum inspection during a pre-trip?

Choose one answer below.

ATo check if the drums are painted correctly✓BTo look for cracks, broken welds, or holes and to check that the drum is not contaminated with oil or grease✓CTo measure the exact diameter of the drum with calipers✓DTo verify the brand of the brake drum✓

QUESTION 15 / 25

When checking air brake lines during a pre-trip inspection, the driver should look for:

Choose one answer below.

ALines that are properly color-coded only✓BCuts, cracks, abrasion damage, and that lines are properly secured and not in contact with hot surfaces✓COnly whether the lines are connected at both ends✓DWhether the lines are made of rubber or metal✓

QUESTION 16 / 25

Recapped or retreaded tires are NOT permitted on which axle position of a commercial motor vehicle?

Choose one answer below.

ADrive axle✓BTrailer axle✓CSteer axle✓DThey are permitted on all axle positions✓

QUESTION 17 / 25

When inspecting suspension components during a pre-trip, what defects should a driver look for on the leaf springs?

Choose one answer below.

AOnly check that the springs are present✓BCracked, broken, shifted, or missing leaves, and broken or missing u-bolts✓CCheck the spring color and coating✓DMeasure the spring length to verify it is correct✓

QUESTION 18 / 25

A tire on a dual wheel assembly is found to be flat during inspection. What should the driver do?

Choose one answer below.

ADrive slowly to the nearest tire shop since the other tire in the dual will support the load✓BHave the flat tire repaired or replaced before driving; do not drive on a flat tire even in a dual assembly✓CRemove the flat tire and drive on the single remaining tire✓DInflate the tire and continue if no visible damage is present✓

QUESTION 19 / 25

When should you place your reflective triangles after stopping on the road due to a breakdown?

Choose one answer below.

AWithin 30 minutes of stopping✓BWithin 10 minutes of stopping✓COnly if it is dark outside✓DOnly on highways with speed limits over 55 mph✓

QUESTION 20 / 25

How should you adjust your mirrors on a commercial motor vehicle?

Choose one answer below.

ASo you can see only the road behind you✓BSo you can see just a small portion of the trailer body along with the road behind and to the sides✓CSo you can see only the trailer doors✓DMirrors only need adjustment when pulling a new trailer✓

QUESTION 21 / 25

Which types of lights must be checked during a pre-trip inspection?

Choose one answer below.

AOnly headlights and tail lights✓BHeadlights (high and low beam), tail lights, brake lights, turn signals, four-way flashers, clearance/marker lights, and identification lights✓COnly the lights that face forward✓DOnly brake lights and turn signals✓

QUESTION 22 / 25

What is the difference between flat (plane) mirrors and convex mirrors on a commercial motor vehicle?

Choose one answer below.

AThey function identically but are different shapes✓BFlat mirrors provide an accurate image while convex mirrors provide a wider field of view but make objects appear farther away than they actually are✓CConvex mirrors provide an accurate image while flat mirrors distort distances✓DConvex mirrors are only used on the passenger side✓

QUESTION 23 / 25

Clearance lights on a commercial motor vehicle serve what primary purpose?

Choose one answer below.

ATo illuminate the road directly in front of the vehicle✓BTo indicate the overall width and height of the vehicle to other drivers, especially at night✓CTo signal lane changes✓DTo provide lighting inside the cargo area✓

QUESTION 24 / 25

How often should a driver check their mirrors while driving a commercial motor vehicle?

Choose one answer below.

AEvery 30 seconds✓BEvery 5 to 8 seconds✓COnly when changing lanes✓DEvery 2 minutes✓

QUESTION 25 / 25

During a pre-trip inspection, you discover that one of the rear identification lights (the three red lights at the top rear of the trailer) is burned out. What action should you take?

Choose one answer below.

AIt is acceptable to drive since the other two identification lights are still working✓BReplace the bulb or have it repaired before driving, as all required lights must be operational✓CCover the burned-out light with red tape to simulate the light✓DIdentification lights are optional on trailers and do not need to be working✓