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The CDL general knowledge test is required to be taken by all CDL applicants. The Iowa CDL test consists of 50 questions. To pass, you must correctly answer at least 40 questions (80%). The general knowledge test covers the contents of the Iowa CDL Manual. All CDL applicants (Class A, B and C) must study the following sections: Driving Safely, Transporting Cargo Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Vehicle Inspection Test, Basic Control Skills Test, Road Test. In addition, the Class A CDL test will include questions based on the Combination Vehicles section. Take this CDL practice test now to prepare for the actual IA general knowledge test! To get your CDL, you must pass both the knowledge and skills tests. CDL knowledge tests include: General Knowledge, Passenger Transport, Air Brakes, Combination Vehicles, Hazardous Materials, Tanker Vehicles, Doubles/Triples, School Bus, Firefighter. Depending on what class of license (A, B or C) and endorsements you need, you must take one or more knowledge tests. A special endorsement is also required to drive certain types of vehicles. The following endorsements may be used with a Class A, B or C CDL: HazMat (H), Tank Vehicles (N), Tank Vehicles Transporting Hazardous Materials (X) and Passenger Transport (P). The School Bus endorsement (S) is only available for Class A or B CDL, and the Doubles/Triples endorsement (T) is only available for Class A driver's licenses.
1. When checking tires, which of the following is not a problem?
Cracked valve stems
Too much air pressure
4/32 inch tread depth on front tires
2. While driving at night, use __________ when it is safe and legal to do so.
interior lights
high beams
low beams
3. When approaching a vehicle as part of a pre-trip inspection, which of the following could be a sign of trouble?
Inflated tires
Fresh oil under the vehicle
Parking brake is on
4. When only the tractor has ABS:
you should be able to maintain steering control during braking.
there is a greater chance of jackknifing.
the trailer is less likely to swing out.
5. When driving in heavy traffic, the safest speed is:
5 mph below the posted speed limit.
the speed of other vehicles, up to the posted limit.
the posted speed limit.
6. What is the minimum number of tie-downs for a 20 foot load?
7. Which of the following vehicles is most likely to turn over?
3 axle tractor semitrailer
65 ft. conventional double
Triple trailer
8. Before starting down a hill, you should slow down and shift down:
to a speed that you can control without using the brakes hard.
so you can coast downhill.
to a gear that will cause your engine to exceed its redline.
9. Driving in very hot weather:
can decrease oil pressure.
should never be done.
can increase tire pressure.
10. The height of a vehicle's center of gravity is important for safe handling. Why?
A high center of gravity means you are less likely to tip over.
Trucks with a high center of gravity have better traction.
Trucks with a high center of gravity can roll over at the posted speed limit for a curve.
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IA CDL Practice Test

Number of questions: 50
Correct answers to pass:40
Passing score:80%
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