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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 going down a long downgrade, the speed of your vehicle will likely:
stay the same.
2. Suspension systems:
have a weight capacity rating.
have a minimum weight rating.
are rated for the maximum weight the vehicle can pull.
3. What is an "escape ramp"?
A short section of road by which traffic may leave a controlled access highway.
A ramp built on steep mountain downgrades, made to stop runaway vehicles safely.
A road shoulder made to support the weight of large vehicles and, therefore, offer an escape route.
4. If you do not have a cell phone or CB, the first thing you should do at an accident scene is to:
clear the area.
protect the accident area.
care for the injured.
5. Which of the following is not a type of retarder?
6. Air tank drains:
are used to remove water and oil from the air tanks.
should not be used in wet weather.
protect the tanks and the rest of the system from too much pressure.
7. If you must drive through a deep puddle you should:
apply the brakes until your speed reaches 40 mph.
speed up to get through the puddle as quickly as possible.
slow down and place transmission in a low gear.
8. If you hear a loud loud "bang" and the steering feels "heavy", you should:
hold the steering wheel firmly and stay off the brake.
brake hard and pull off the road.
pump the brakes until the vehicle has slowed down.
9. When driving in very hot weather, you may have to:
increase your speed until the tires cool off.
reduce your speed to prevent overheating.
decrease your following distance.
10. In cool weather, as the temperature rises to the point where ice begins to melt:
it is safe to drive.
the road will become more slippery.
black will makes the road look wet.
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IA CDL Knowledge Test

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