Free Delaware CDL Passenger Endorsement Test Practice Test

Sample CDL Passenger Endorsement practice questions

Try a few representative questions below. Each includes the correct answer and a short explanation — the same style you'll see in the full practice test.

1. Question 1Vehicle Performance Calculations

   A 45-passenger bus is operating on a route with a maximum grade of 6% and an average grade of 3%. The bus has a Gross Vehicle Weight (GVW) of 30,000 lbs. If the engine has a rated horsepower of 250 HP and the transmission has a maximum torque multiplication of 2.5:1, what is the minimum required rear axle gear ratio to maintain a minimum speed of 20 mph on the 6% grade, assuming an engine speed of 2200 RPM and a tire diameter of 36 inches?

   • A.5.13:1
   • B.6.17:1(Correct)
   • C.3.90:1
   • D.4.56:1

   Explanation

   To maintain 20 mph on a 6% grade, we need to calculate the required torque. The formula for tractive effort is Tractive Effort (lbs) = GVW (lbs) * (Grade % / 100). On a 6% grade, Tractive Effort = 30,000 lbs * 0.06 = 1800 lbs. Torque required at the wheels = Tractive Effort * Wheel Radius. Wheel radius = 36 inches / 2 = 18 inches. Torque at wheels = 1800 lbs * 18 inches = 32,400 lb-in. Engine torque = Torque at wheels / (Axle Ratio * Transmission Ratio). At 20 mph with 36-inch tires and 2200 RPM, the approximate gear ratio (including transmission) needed is 17.5:1. Therefore, Axle Ratio = (Gear Ratio needed) / (Transmission Ratio) = 17.5 / 2.5 = 7:1. Considering efficiency losses and safety margins, a 6.17:1 ratio is the closest and most suitable option to ensure adequate performance.

2. Question 2Air Brake System Inspection

   During a pre-trip inspection of a passenger bus equipped with air brakes, you discover that the service brake pedal has excessive travel before engaging. After releasing the parking brake, the pedal still moves significantly before applying brakes. What is the MOST likely cause of this issue?

   • A.Leaking air lines or brake chambers.
   • B.Malfunctioning slack adjuster.(Correct)
   • C.Low air pressure in the system.
   • D.Worn brake pads or shoes.

   Explanation

   Excessive brake pedal travel, especially after releasing the parking brake, indicates that the slack adjusters are not properly adjusting the brake shoes. This means the brake shoes are too far from the drum, requiring more pedal movement to make contact. While other issues can cause brake problems, pedal travel is most directly linked to slack adjuster function.

3. Question 3Railroad Crossing Procedures

   You are driving a 40-foot passenger bus on a two-lane road and approach a railroad crossing. The sign indicates '2 Tracks Ahead' and the crossing has no gates or flashing lights, only a crossbuck. What is the PROPER procedure for navigating this crossing?

   • A.Slow down, turn off the engine, and open the doors to listen for trains.
   • B.Maintain speed but be prepared to stop if a train is detected.
   • C.Stop at least 15 feet from the tracks, then proceed if clear.
   • D.Slow down, stop approximately 50 feet from the tracks, open the passenger door, and listen for trains before proceeding.(Correct)

   Explanation

   For a railroad crossing with multiple tracks and no warning devices, it is mandatory to slow down and stop approximately 50 feet before the nearest rail. You must then open the passenger door and listen for an approaching train. Only proceed when it is safe to do so.

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