Oklahoma CDL Combination Practice Test (OK) 2

5 out of 5 (41 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for your Oklahoma CDL Combination test? Our Oklahoma combination CDL practice test is designed to help you master the skills and knowledge needed to pass the official test with confidence. This CDL combination practice test includes 20 multiple-choice questions that cover essential topics like inspection procedures, safe driving practices, air brake systems, and more. To pass, you need to answer at least 16 questions correctly. Understanding the unique driving conditions across Oklahoma is crucial for aspiring truck drivers. Whether you're navigating the busy streets of Oklahoma City, the rural roads of the panhandle, or the challenging weather conditions that can sweep across the state, having a firm grasp on the fundamentals is key. For instance, the combination CDL test emphasizes the importance of recognizing the dangers of jackknifing. By learning how to manage smooth braking and careful handling, you'll be better prepared to tackle Oklahoma's diverse terrains and weather conditions. The Oklahoma written driving test practice is easily accessible online through your desktop, mobile, or app, ensuring you can study whenever and wherever it suits you best. Unlike other tests, there are no time limits on this permit test practice, allowing you to focus on understanding each question thoroughly without the pressure of the clock ticking. Our Oklahoma DMV practice test is crafted to give you an authentic experience that closely mirrors the actual DMV permit test. While the DMV doesn't publish their questions, our Oklahoma practice permit test covers identical topics with comparable phrasing, enabling you to grasp essential concepts effectively. This ensures that when you sit for the real test, you'll be familiar with the format and the types of questions you'll encounter. This CDL combination practice test not only prepares you for the official test but also instills the confidence needed to become a safe and competent driver on Oklahoma's roads. Take advantage of this permit practice test to enhance your preparation and increase your chances of success.
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Sample Oklahoma Combination Test Questions

Question 1

Where are air-line shut-off valves normally located on trailers used to pull another trailer?

  1. A Inside the tractor cab
  2. B Beside the tractor’s fifth wheel
  3. C At the front of the first trailer
  4. D At the rear of the trailer

Correct answer: D – At the rear of the trailer

Shut-off valves, also called cut-out cocks, are installed in the service and emergency or supply lines at the rear of trailers designed to tow another trailer. They allow the air lines to be closed when another trailer is not attached. The valves at the rear of the last trailer must be closed during normal operation.

Source: Oklahoma Commercial Driver’s License Manual — § 6.2.7, “Shut-off Valves”

Question 2

What should you do if an inspection shows that the service and emergency air lines were crossed during coupling?

  1. A Drive slowly until the lines correct themselves
  2. B Release the tractor parking brake
  3. C Use only the trailer hand valve while driving
  4. D Reconnect the lines correctly and retest the brakes before driving

Correct answer: D – Reconnect the lines correctly and retest the brakes before driving

Crossed lines can prevent the trailer tanks from charging and the spring brakes from releasing. On some older trailers, the vehicle might move without functioning trailer brakes. Connect the service line to the service glad hand and the emergency line to the emergency glad hand, then test the trailer brakes before driving.

Source: Oklahoma Commercial Driver’s License Manual — § 6.2.5, “Hose Couplers (Glad Hands)”

Question 3

A fully loaded combination rig is about ten times more likely to roll over in a crash than an empty rig.

  1. A True
  2. B False

Correct answer: A – True

The CDL manual states that fully loaded rigs are ten times more likely to roll over in a crash than empty rigs. Stacking cargo higher raises the center of gravity and makes the vehicle easier to overturn. Keeping the load low and centered and reducing speed before turns helps control this risk.

Source: Oklahoma Commercial Driver’s License Manual — § 6.1.1, “Rollover Risks”

Question 4

Which procedure correctly checks a trailer’s service brakes?

  1. A Build normal air pressure, move forward slowly, and apply the trailer brakes with the hand control
  2. B Pull out the trailer air-supply control and accelerate against the brakes
  3. C Shut off the engine and pump the brake pedal until the tanks are empty
  4. D Release every parking brake and allow the combination to roll freely

Correct answer: A – Build normal air pressure, move forward slowly, and apply the trailer brakes with the hand control

With normal air pressure, release the parking brakes and move the combination forward slowly. Apply the trailer brakes with the hand control, if equipped, and verify that you feel them engage. The Oklahoma manual specifies the hand valve for this test, while the foot pedal should control braking during normal operation.

Source: Oklahoma Commercial Driver’s License Manual — § 6.5.2, “Combination Vehicle Brake Check”

Question 5

While moving a combination vehicle slowly, which action verifies that the trailer service brakes are connected and working?

  1. A Apply the trailer brakes with the hand valve and feel for braking
  2. B Accelerate rapidly and release the clutch
  3. C Make a sharp turn while applying the foot brake
  4. D Check whether the trailer brake lamps illuminate

Correct answer: A – Apply the trailer brakes with the hand valve and feel for braking

After confirming normal air pressure and releasing the parking brakes, move forward slowly and apply the trailer hand control, if the vehicle has one. Feeling the trailer brakes engage verifies that they are connected and operating. During ordinary driving, use the foot brake rather than the trailer hand valve.

Source: Oklahoma Commercial Driver’s License Manual — § 6.5.2, “Combination Vehicle Brake Check”

Question 6

Why is the trailer hand valve not a proper parking method?

  1. A On a trailer without spring brakes, air can leak away and release the brakes
  2. B It permanently locks the trailer wheels
  3. C It disconnects the tractor protection valve
  4. D It lowers the trailer landing gear

Correct answer: A – On a trailer without spring brakes, air can leak away and release the brakes

The hand valve applies the trailer brakes using air pressure, but air can gradually leak from the system. On trailers without spring brakes, that loss can release the brakes and allow the trailer to move. Use the vehicle’s parking brakes when parking and chock the wheels when parking a trailer that lacks spring brakes.

Source: Oklahoma Commercial Driver’s License Manual — § 6.2.1, “Trailer Hand Valve”; § 6.2.8, “Trailer Service, Parking and Emergency Brakes”

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