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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. The steering wheel should:
be held firmly with both hands.
be held firmly with the left hand.
be held firmly with the right hand.
2. What should you do to test your hydraulic brakes for leaks?
Pump the brake pedal five times, then apply pressure for three seconds.
Hold the brake pedal down for five seconds, then pump it three times.
Pump the brake pedal three times, then apply pressure to the pedal and hold for five seconds.
3. When driving in hot weather:
the the tires' air pressure will decrease.
the engine oil helps keep the engine cool, as well as lubricate it.
antifreeze should be avoided.
4. If your vehicle thumps or vibrates heavily, it may be a sign that:
the brakes have failed.
one of the tires has gone flat.
you need to shift up.
5. When water collects on the road. your vehicle can:
stop suddenly.
6. Why should you check your mirrors regularly to know where other vehicles are around you?
To know whether you can make a quick lane change in an emergency.
To move out of their way if they want to get past.
To flash the brake lights if you are being tailgated.
7. Before driving a vehicle with a dual brake brake system, the driver should:
wait at least 10 minutes before driving.
pump the brake pedal 10 times to build pressure.
allow time for the air compressor to build up a minimum of 100 psi pressure in both the primary and secondary systems.
8. After starting the engine the coolant temperature should:
rise gradually.
rise quickly.
slowly decrease.
9. When driving in heavy traffic, the safest speed is:
slower than the speed of other traffic.
the posted speed limit.
the speed of traffic.
10. B:C type fire extinguishers are suitable for dealing with:
wood fires.
tire fires.
electrical fires and burning liquids.
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IA CDL Practice Test

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