CDL COMBINATION VEHICLE EXAM, PRACTICE EXAM AND STUDY GUIDE NEWEST 2026 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH

CDL COMBINATION VEHICLE EXAM, PRACTICE EXAM AND STUDY GUIDE NEWEST 2026 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH ( ANSWERS)

CDL COMBINATION VEHICLE EXAM, PRACTICE EXAM AND STUDY GUIDE NEWEST 2026 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH ( ANSWERS) Before a drive, ensure that air flows to all trailers by: - ANSWER- Opening the rear shut-off valves and listening for escaping air. Test the tractor protection valve by: - ANSWER- Releasing air with the brake pedal. Pull out the trailer air supply control to test: - ANSWER- The trailer emergency brakes. To prevent a rollover, a driver should: - ANSWER- Keep cargo low. One way to prevent a rollover is to: - ANSWER- Keep cargo centered on the rig. In a sudden turn, the ____ trailer is the most likely to turn over. - ANSWER- Last. Using the trailer hand brake while experiencing a trailer jackknife will: - ANSWER- Continue the skid. If you need to back your trailer but cannot back up in a straight path, you should: - ANSWER- Back toward the driver's side. Using the trailer hand valve while driving: - ANSWER- Can cause a skid. Push in the trailer air supply control to: - ANSWER- Supply the trailer with air. In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when: - ANSWER- Air pressure drops to a level between 20 and 45 psi. An air supply control in its "emergency" position will: - ANSWER- Apply the trailer emergency brakes. The service air line is attached to the: - ANSWER- Relay valves. The emergency air line: - ANSWER- Supplies air to the trailer air tanks. Trailers built before 1975 are: - ANSWER- Not required to have spring brakes. While inspecting a coupling, you should go under the trailer and: - ANSWER- Look into the back of the fifth wheel. If you are operating a vehicle built before 1998 and are unsure if the trailer has an Anti-Lock Braking System (ABS), you can: - ANSWER- Check for wheel speed sensors coming from the back of the brakes. After finishing a pre-trip inspection, you should: - ANSWERClose the emergency line valve. Close the service line valve. During a trip, which shut-off valves should be open? - ANSWER- All shut-off valves should be in the open position, except the rear shut-off valves. To test the trailer service brakes, you should: - ANSWER- Move the vehicle forward slowly and apply the brakes with the hand control. ____ are the cause of more than half of all accident-related truck driver deaths. - ANSWER- Truck rollovers. When traveling more slowly than 40 mph, maintain at least ____ of following distance per every 10 feet of your vehicle. - ANSWER- One second. Avoid needing to make sudden lane changes by: - ANSWERWatching the road ahead while driving. A lightly-loaded combination vehicle will stop more slowly than a fully loaded vehicle because: - ANSWER- The stiff suspension springs and strong brakes will have low traction. When driving a bobtail tractor, you should be aware that: - ANSWER- Bobtails are more difficult to stop than tractors with semitrailers.