Iowa General Knowledge Practice Test
This is our Iowa General Knowledge Practice Quiz and Practice Test compiled of 50 questions each. Each question is worth two points for a total of 100 possible points. A passing score is 80%.
The General Knowledge Practice Quiz reveals the correct answer during each question to help you study for the actual General Knowledge test. The General Knowledge Practice Test doesn’t reveal the correct answers until the test is over.
The questions and answers are given in random order each time you retake the test. When you are finished testing, simply click on the “Get Results” button to see your test results. Clicking on the blue “List” button will reveal a list of all the questions you answered correctly and incorrectly. To take the test again, just refresh your browser window. It’s that easy.
Press the start button to begin your free General Knowledge Practice Quiz. Good luck!
General Knowledge CDL Practice Quiz

Question 1 |
A | The same amount of space you would at night. |
B | The same amount of space you would on a dry road. |
C | One vehicle length for every 10,000 lb. of gross vehicle weight. |
D | More space than is needed for ideal driving conditions. |
Question 2 |
A | there is ice and snow, to prevent skidding. |
B | it is absolutely necessary. |
C | you will be parked for a short time. |
D | testing the trailer brakes after hooking up to a trailer. |
Question 3 |
A | two |
B | three |
C | four |
D | one |
Question 4 |
A | leaks |
B | rust |
C | burning |
D | rubbing |
Question 5 |
A | exempt from hazardous materials restrictions. |
B | generally used when freight is carried part way by rail or ship. |
C | exempt from height restrictions. |
D | exempt from weight limit restrictions. |
Question 6 |
A | the load should not get wet. |
B | the load can catch fire easily. |
C | the load can shift. |
D | a dry bulk tank should only be filled halfway. |
Question 7 |
A | A minimum of two. |
B | A minimum of four. |
C | A minimum of one. |
D | A minimum of three. |
Question 8 |
A | safely remove the radiator cap and add coolant while the engine is hot. |
B | use only water in the cooling system. |
C | use windshield washer fluid as coolant. |
D | check the coolant level of a hot engine. |
Question 9 |
A | two times |
B | half |
C | three times |
D | four times |
Question 10 |
A | Because some of the heaviest liquids don’t need any. |
B | Because some liquids expand more than others when they get warm. |
C | Because it's good to know that information. |
D | Because tank baffles are not always legal with outage. |
Question 11 |
A | rolled down windows |
B | rear view cameras |
C | mirrors |
D | sunglasses |
Question 12 |
A | the brake pedal feels firm when you apply pressure. |
B | you release pressure on the brake pedal and speed increases. |
C | you have to push harder and harder to get the same stopping power on a downgrade. |
D | there is a slight vibration when you press down on the brake pedal. |
Question 13 |
A | to ensure safety for yourself, your passengers, and other drivers. |
B | because it is a requirement for all drivers. |
C | to help ensure the vehicle will make it to your destination. |
D | because law enforcement may inspect your vehicle on the road. |
Question 14 |
A | turn wide as you complete the turn |
B | turn wide before you start the turn |
C | turn right and drive over the curb |
D | start the turn, then back up to re-position |
Question 15 |
A | roll down your window so that the fresh air will help keep you awake. |
B | drink coffee or other caffeine products to help keep you awake. |
C | make sure you are driving slow enough so you can stop within the range of your headlights in case of an emergency. |
D | keep your high beams on at all times. |
Question 16 |
A | at least once a week. |
B | before operating the vehicle. |
C | if any problems occurred the last the time the vehicle was operated. |
D | whenever you stop to refuel. |
Question 17 |
A | check to make sure that the brakes are properly balanced. |
B | downshift into the turn. |
C | keep two hands firmly planted on the steering wheel at all times. |
D | keep the cargo as close to the ground as possible. |
Question 18 |
A | the wheel needs cleaning. |
B | the lug nut needs to be replaced. |
C | the lug nut is cheap. |
D | the lug nut is loose. |
Question 19 |
A | Perception distance, reaction distance, and braking distance. |
B | Perception distance, slowing distance, and braking distance. |
C | Observation distance, reaction distance, and slowing distance. |
D | Perception distance, response distance, and reaction distance. |
Question 20 |
A | 4/32-inch in every major groove. |
B | 3/32-inch in every major groove. |
C | 2/32-inch in every major groove. |
D | 5/32-inch in every major groove. |
Question 21 |
A | both of these. |
B | the weight of the liquid. |
C | neither of these. |
D | the legal weight limits. |
Question 22 |
A | placard numbers match the seal numbers. |
B | seal is secure. |
C | load is properly secured. |
D | seal is authentic. |
Question 23 |
A | loose fuel connections |
B | under inflated tires |
C | both loose fuel connections and under inflated tires |
D | eating spicy food in the truck cab |
Question 24 |
A | have the same stopping distance as full trucks |
B | have better traction when stopping than full trucks |
C | need less space ahead than full trucks |
D | require greater stopping distance than full trucks |
Question 25 |
A | to avoid mixing hazmat with food. |
B | to make your vehicle look official. |
C | to combat terrorism. |
D | to warn others of hazardous materials. |
Question 26 |
A | seven or more. |
B | three or more. |
C | none of these. |
D | five or more. |
Question 27 |
A | Turn on your four-way flashers as you approach the offramp. |
B | Downshift after you are in the curve. |
C | Slow to a safe speed before the curve. |
D | Nothing, because the posted speed limit for the offramp is usually 10 miles per hour below the safe speed limit for the offramp. |
Question 28 |
A | driving too slow for road conditions. |
B | poorly adjusted brakes. |
C | driving too fast for road conditions. |
D | bad tires. |
Question 29 |
A | Play in the steering wheel of more than ten degrees (two inches on a 20-inch steering wheel). |
B | Play in the steering wheel of more than five degrees. |
C | Oil on the tie rod. |
D | Too many vertical stacks. |
Question 30 |
A | before going up a hill and before entering a curve. |
B | before starting down a hill and before entering a curve. |
C | before starting down a hill and before going up a hill. |
D | before starting down a hill and before entering a tunnel. |
Question 31 |
A | you want to avoid doing something all of a sudden. |
B | it is a federal law. |
C | you want to have a plan to communicate the risk. |
D | you want to have time to act before it turns into an emergency. |
Question 32 |
A | offtracking. |
B | sidetracking. |
C | fishtailing. |
D | slidetracking. |
Question 33 |
A | Shorter stopping distance. |
B | It depends on what mood you are in at the time. |
C | The same amount of stopping distance. |
D | Greater stopping distance. |
Question 34 |
A | Load more weight over the drive axle for better traction. |
B | Load more cargo toward the front of the truck for a full load. |
C | Load cargo weight evenly over all the axles. |
D | Load cargo toward the rear of the truck for easier unloading. |
Question 35 |
A | slap yourself in the face three times. |
B | roll down the windows. |
C | stop to sleep. |
D | turn up the radio. |
Question 36 |
A | one inch |
B | three inches |
C | two inches |
D | one half inch |
Question 37 |
A | Put your warning devices out within 15 minutes. |
B | Keep your low beam lights on. |
C | Turn on your 4-way emergency flashers to warn other drivers. |
D | Warn other drivers by using your left turn signal lights. |
Question 38 |
A | To watch for steering errors. |
B | To prevent others from distracting you. |
C | To direct traffic away from you. |
D | To see the blind spots you can't see. |
Question 39 |
A | you are driving on hilly, rural roads. |
B | you are driving on the freeway. |
C | road conditions are excellent. |
D | the road is wet, icy, or snow covered. |
Question 40 |
A | Judgment and self-control are the first to be affected. |
B | All of these things happen. |
C | Muscle control and coordination are affected. |
D | The drinker's brain is increasingly affected. |
Question 41 |
A | law enforcement officers, detours |
B | truck stops, gas stations |
C | tunnels, overpasses |
D | vehicles, traffic signs |
Question 42 |
A | increases when the service brakes are hot. |
B | depends on the service brakes being in adjustment. |
C | decreases when the service breaks are hot. |
D | is not affected by the condition of the service brakes. |
Question 43 |
A | the end of the kingpin is even with the top of the fifth wheel. |
B | the kingpin is about 1¼ inches above the fifth wheel. |
C | the end of the kingpin is at waist level. |
D | it will be raised slightly when the tractor is backed under it. |
Question 44 |
A | the trailer is out of brake adjustment. |
B | the trailer is fully loaded or very heavy. |
C | the trailer is being hauled at high speed. |
D | the trailer is empty or lightly loaded. |
Question 45 |
A | over-heated brakes, under-inflated tires |
B | poor-quality retreads, under-inflated tires |
C | dual tires that touch, hot road surfaces |
D | under-inflated tires, dual tires that touch |
Question 46 |
A | Road construction zones. |
B | All of these are considered a hazard. |
C | Pedestrians and bicyclists. |
D | A stopped transit bus. |
Question 47 |
A | Electrical fire. |
B | None of these fires can be safely extinguished by water. |
C | Gasoline fire. |
D | Grease fire. |
Question 48 |
A | Shift the truck into neutral and coast down the hill to save gas. |
B | Use the same gear you would use to climb the hill. |
C | Use a higher gear than you would use to climb the hill. |
D | Use a lower gear than you would use to climb the hill. |
Question 49 |
A | Using turn signals, 4-way flashers, headlights, and the horn. |
B | Using your CB radio or cell phone to inform others. |
C | Using hand signals. |
D | Using a helper when backing up. |
Question 50 |
A | Push the brake pedal firmly 5 seconds; listen for leaks. |
B | Pump the brake pedal 5 times; push the pedal firmly 3 seconds; the pedal should not move. |
C | Pump the brake pedal 3 times; push the pedal firmly 5 seconds; the pedal should not move. |
D | Move forward slowly and push firmly on the brake pedal. |
← | List | → |
1 | 2 | 3 | 4 | 5 |
6 | 7 | 8 | 9 | 10 |
11 | 12 | 13 | 14 | 15 |
16 | 17 | 18 | 19 | 20 |
21 | 22 | 23 | 24 | 25 |
26 | 27 | 28 | 29 | 30 |
31 | 32 | 33 | 34 | 35 |
36 | 37 | 38 | 39 | 40 |
41 | 42 | 43 | 44 | 45 |
46 | 47 | 48 | 49 | 50 |
End |
Remember, the General Knowledge Practice Test doesn’t reveal the correct answers until the test is over. The questions and answers are given in random order each time you retake the test. When you are finished testing, simply click on the “Get Results” button to see your test results. Clicking on the blue “List” button will reveal a list of all the questions you answered correctly and incorrectly. To take the test again, just refresh your browser window.
Press the start button to begin your free General Knowledge Practice Test. Good luck!
General Knowledge CDL Practice Test

Question 1 |
A | Warn other drivers by using your left turn signal lights. |
B | Keep your low beam lights on. |
C | Turn on your 4-way emergency flashers to warn other drivers. |
D | Put your warning devices out within 15 minutes. |
Question 2 |
A | a dry bulk tank should only be filled halfway. |
B | the load can catch fire easily. |
C | the load should not get wet. |
D | the load can shift. |
Question 3 |
A | bad tires. |
B | driving too fast for road conditions. |
C | poorly adjusted brakes. |
D | driving too slow for road conditions. |
Question 4 |
A | you have to push harder and harder to get the same stopping power on a downgrade. |
B | there is a slight vibration when you press down on the brake pedal. |
C | the brake pedal feels firm when you apply pressure. |
D | you release pressure on the brake pedal and speed increases. |
Question 5 |
A | Oil on the tie rod. |
B | Play in the steering wheel of more than five degrees. |
C | Play in the steering wheel of more than ten degrees (two inches on a 20-inch steering wheel). |
D | Too many vertical stacks. |
Question 6 |
A | the end of the kingpin is even with the top of the fifth wheel. |
B | it will be raised slightly when the tractor is backed under it. |
C | the kingpin is about 1¼ inches above the fifth wheel. |
D | the end of the kingpin is at waist level. |
Question 7 |
A | keep two hands firmly planted on the steering wheel at all times. |
B | downshift into the turn. |
C | keep the cargo as close to the ground as possible. |
D | check to make sure that the brakes are properly balanced. |
Question 8 |
A | tunnels, overpasses |
B | vehicles, traffic signs |
C | law enforcement officers, detours |
D | truck stops, gas stations |
Question 9 |
A | one |
B | three |
C | two |
D | four |
Question 10 |
A | sidetracking. |
B | offtracking. |
C | fishtailing. |
D | slidetracking. |
Question 11 |
A | road conditions are excellent. |
B | the road is wet, icy, or snow covered. |
C | you are driving on the freeway. |
D | you are driving on hilly, rural roads. |
Question 12 |
A | loose fuel connections |
B | overinflated tires |
C | underinflated tires |
D | both loose fuel connections and under inflated tires |
Question 13 |
A | Because some liquids expand more than others when they get warm. |
B | Because it's good to know that information. |
C | Because tank baffles are not always legal with outage. |
D | Because some of the heaviest liquids don’t need any. |
Question 14 |
A | mirrors |
B | rear view cameras |
C | rolled down windows |
D | sunglasses |
Question 15 |
A | it is absolutely necessary. |
B | you will be parked for a short time. |
C | testing the trailer brakes after hooking up to a trailer. |
D | there is ice and snow, to prevent skidding. |
Question 16 |
A | to combat terrorism. |
B | to avoid mixing hazmat with food. |
C | to make your vehicle look official. |
D | to warn others of hazardous materials. |
Question 17 |
A | Move forward slowly and push firmly on the brake pedal. |
B | Push the brake pedal firmly 5 seconds; listen for leaks. |
C | Pump the brake pedal 3 times; push the pedal firmly 5 seconds; the pedal should not move. |
D | Pump the brake pedal 5 times; push the pedal firmly 3 seconds; the pedal should not move. |
Question 18 |
A | depends on the service brakes being in adjustment. |
B | increases when the service brakes are hot. |
C | decreases when the service breaks are hot. |
D | is not affected by the condition of the service brakes. |
Question 19 |
A | exempt from hazardous materials restrictions. |
B | exempt from weight limit restrictions. |
C | generally used when freight is carried part way by rail or ship. |
D | exempt from height restrictions. |
Question 20 |
A | dual tires that touch, hot road surfaces |
B | under-inflated tires, dual tires that touch |
C | over-heated brakes, under-inflated tires |
D | poor-quality retreads, under-inflated tires |
Question 21 |
A | make sure you are driving slow enough so you can stop within the range of your headlights in case of an emergency. |
B | roll down your window so that the fresh air will help keep you awake. |
C | keep your high beams on at all times. |
D | drink coffee or other caffeine products to help keep you awake. |
Question 22 |
A | use windshield washer fluid as coolant. |
B | check the coolant level of a hot engine. |
C | use only water in the cooling system. |
D | safely remove the radiator cap and add coolant while the engine is hot. |
Question 23 |
A | have the same stopping distance as full trucks |
B | need less space ahead than full trucks |
C | require greater stopping distance than full trucks |
D | have better traction when stopping than full trucks |
Question 24 |
A | Use a higher gear than you would use to climb the hill. |
B | Shift the truck into neutral and coast down the hill to save gas. |
C | Use a lower gear than you would use to climb the hill. |
D | Use the same gear you would use to climb the hill. |
Question 25 |
A | Perception distance, response distance, and reaction distance. |
B | Perception distance, reaction distance, and braking distance. |
C | Perception distance, slowing distance, and braking distance. |
D | Observation distance, reaction distance, and slowing distance. |
Question 26 |
A | Gasoline fire. |
B | Grease fire. |
C | Electrical fire. |
D | None of these fires can be safely extinguished by water. |
Question 27 |
A | half |
B | three times |
C | two times |
D | four times |
Question 28 |
A | rubbing |
B | rust |
C | burning |
D | leaks |
Question 29 |
A | to help ensure the vehicle will make it to your destination. |
B | because it is a requirement for all drivers. |
C | because law enforcement may inspect your vehicle on the road. |
D | to ensure safety for yourself, your passengers, and other drivers. |
Question 30 |
A | if any problems occurred the last the time the vehicle was operated. |
B | before operating the vehicle. |
C | at least once a week. |
D | whenever you stop to refuel. |
Question 31 |
A | Road construction zones. |
B | A stopped transit bus. |
C | Pedestrians and bicyclists. |
D | All of these are considered a hazard. |
Question 32 |
A | before starting down a hill and before going up a hill. |
B | before going up a hill and before entering a curve. |
C | before starting down a hill and before entering a tunnel. |
D | before starting down a hill and before entering a curve. |
Question 33 |
A | three inches |
B | two inches |
C | one inch |
D | one half inch |
Question 34 |
A | stop to sleep. |
B | roll down the windows. |
C | slap yourself in the face three times. |
D | turn up the radio. |
Question 35 |
A | the lug nut needs to be replaced. |
B | the wheel needs cleaning. |
C | the lug nut is cheap. |
D | the lug nut is loose. |
Question 36 |
A | Load more weight over the drive axle for better traction. |
B | Load cargo weight evenly over all the axles. |
C | Load cargo toward the rear of the truck for easier unloading. |
D | Load more cargo toward the front of the truck for a full load. |
Question 37 |
A | turn wide before you start the turn |
B | turn wide as you complete the turn |
C | turn right and drive over the curb |
D | start the turn, then back up to re-position |
Question 38 |
A | More space than is needed for ideal driving conditions. |
B | The same amount of space you would at night. |
C | The same amount of space you would on a dry road. |
D | One vehicle length for every 10,000 lb. of gross vehicle weight. |
Question 39 |
A | the trailer is being hauled at high speed. |
B | the trailer is fully loaded or very heavy. |
C | the trailer is empty or lightly loaded. |
D | the trailer is out of brake adjustment. |
Question 40 |
A | 5/32-inch in every major groove. |
B | 2/32-inch in every major groove. |
C | 3/32-inch in every major groove. |
D | 4/32-inch in every major groove. |
Question 41 |
A | The same amount of stopping distance. |
B | Shorter stopping distance. |
C | It depends on what mood you are in at the time. |
D | Greater stopping distance. |
Question 42 |
A | Muscle control and coordination are affected. |
B | All of these things happen. |
C | The drinker's brain is increasingly affected. |
D | Judgment and self-control are the first to be affected. |
Question 43 |
A | three or more. |
B | none of these. |
C | seven or more. |
D | five or more. |
Question 44 |
A | Turn on your four-way flashers as you approach the offramp. |
B | Nothing, because the posted speed limit for the offramp is usually 10 miles per hour below the safe speed limit for the offramp. |
C | Slow to a safe speed before the curve. |
D | Downshift after you are in the curve. |
Question 45 |
A | To prevent others from distracting you. |
B | To direct traffic away from you. |
C | To see the blind spots you can't see. |
D | To watch for steering errors. |
Question 46 |
A | placard numbers match the seal numbers. |
B | load is properly secured. |
C | seal is authentic. |
D | seal is secure. |
Question 47 |
A | A minimum of two. |
B | A minimum of one. |
C | A minimum of three. |
D | A minimum of four. |
Question 48 |
A | you want to avoid doing something all of a sudden. |
B | you want to have time to act before it turns into an emergency. |
C | it is a federal law. |
D | you want to have a plan to communicate the risk. |
Question 49 |
A | Using your CB radio or cell phone to inform others. |
B | Using hand signals. |
C | Using a helper when backing up. |
D | Using turn signals, 4-way flashers, headlights, and the horn. |
Question 50 |
A | the weight of the liquid. |
B | both of these. |
C | the legal weight limits. |
D | neither of these. |
← | List | → |
1 | 2 | 3 | 4 | 5 |
6 | 7 | 8 | 9 | 10 |
11 | 12 | 13 | 14 | 15 |
16 | 17 | 18 | 19 | 20 |
21 | 22 | 23 | 24 | 25 |
26 | 27 | 28 | 29 | 30 |
31 | 32 | 33 | 34 | 35 |
36 | 37 | 38 | 39 | 40 |
41 | 42 | 43 | 44 | 45 |
46 | 47 | 48 | 49 | 50 |
End |
Back to Iowa CDL Practice Test