The rear trailer's landing gear has been lowered, but the converter dolly remains under it. A helper proposes opening the first trailer's pintle hook now. What should the driver do?
Correct answer: Keep the pintle locked until the dolly is out
Never unlock the pintle hook with the dolly still beneath the rear trailer. The tow bar can fly upward and cause injury; lowering landing gear is not permission to reverse the specified uncoupling order.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-3, physical 98 > 7.2.2 Uncouple Converter Dolly, pintle-hook warning. ↗
An unloaded dolly has been pulled clear of the rear trailer and its support is lowered. The dolly has no spring brakes. What restraint is needed before releasing it from the first trailer's pintle hook?
Correct answer: Chock the dolly's wheels
The dolly-uncoupling sequence calls for applying the converter gear's spring brakes or chocking its wheels. With no spring brakes in this scenario, chocks provide the specified wheel restraint; the first trailer's brakes cannot hold a disconnected dolly.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-3, physical 98 > 7.2.2 Uncouple Converter Dolly, support and wheel-restraint sequence. ↗
In a training yard, a three-trailer combination is secured for disassembly using the manual's method. Which part is separated first?
Correct answer: The third trailer, then its dolly, using the doubles procedure
The described method starts by removing the third trailer: pull its dolly out, then unhitch that dolly. The remaining combination is then uncoupled as a double.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-3, physical 98 > 7.2.3 Coupling and Uncoupling Triple Trailers, Uncouple Triple-trailer Rig. ↗
Your assigned combination uses a coupling arrangement different from the common configurations shown in the manual. What should establish its coupling and uncoupling procedure?
Correct answer: The manufacturer or owner's specifications for that vehicle
Section 7 does not cover every truck-trailer arrangement. The driver must learn the correct procedure for the actual equipment according to its manufacturer and/or owner specifications.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-3, physical 98 > 7.2.4 Coupling and Uncoupling Other Combinations. ↗
A secured double has normal tractor air pressure and its trailer supply control is pushed in. During the rear supply-line test, no air escapes at the last trailer. Which possible cause does the manual direct you to check?
Correct answer: Whether an upstream trailer or dolly shut-off is closed
The air path must remain open through the preceding trailer and any equipped dolly shut-offs. Normal pressure at the tractor does not prove that air reaches the last trailer. A closed intermediate valve is a possible cause to check, not the only possible fault.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-4, physical 99 > 7.4.1 Additional Air Brake Checks, Check That Air Flows to All Trailers. ↗
During a secured rear-of-rig air-flow check, the supply line passes. No air comes from the service-line outlet, but neither the handbrake nor foot brake is applied. What must be corrected before judging the service-line result?
Correct answer: Apply the trailer handbrake or service-brake pedal
The service-line flow check assumes the trailer handbrake or service-brake pedal is applied to supply a service signal. With neither applied, silence alone does not establish a blocked line. Keep the rig securely held throughout the check.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-4, physical 99 > 7.4.1 Check That Air Flows to All Trailers, service-line brake-application condition. ↗
The converter dolly's air-tank petcock was opened during positioning on a design that uses that method. Coupling is now being completed. What setting does the manual require for that drain before charging the system for travel?
Correct answer: Closed to retain air in the tank
The coupling sequence closes the dolly's air-tank petcock, and the doubles/triples inspection also requires that drain to be closed. Leaving it open for travel is not a method of regulating brake pressure.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-2, 7-3 and 7-4, physical 97, 98 and 99 > 7.2.1 dolly positioning and Connect Converter Dolly to Rear Trailer; 7.3.1 Double and Triple Trailers, drain-valve check. ↗
Both air-flow checks at the rear of the last trailer have passed. Before leaving that location, how should the service and supply shut-off valves at the very end of the rig be left?
Correct answer: Both closed
Each rear outlet is opened briefly for its test and then closed. The last trailer's end valves must be closed; valves needed to pass air onward through preceding trailers stay open.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-4, physical 99 > 7.3.1 Double and Triple Trailers, shut-off settings; 7.4.1 rear supply and service outlet test sequence. ↗
A driver uses the equipped trailer hand valve for the prescribed slow service-brake check. Once driving normally, which control should provide routine service braking?
Correct answer: The foot-brake pedal
The manual distinguishes the trailer hand-valve check from normal operation. Routine braking uses the foot pedal, which applies service braking at all wheels, rather than using the trailer hand valve alone or the supply control.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-5, physical 100 > 7.4.1 Test Trailer Service Brakes, test-control versus normal-operation paragraph. ↗
In a clear test area, the trailer system was charged and free rolling was confirmed. After stopping and setting the trailer supply control to emergency, the trailers still roll freely under a gentle pull. What does that result show?
Correct answer: The check has not confirmed trailer emergency braking
After the charged system is placed in emergency, the gentle pull checks that the trailer emergency brakes are applied. Continued free rolling fails to confirm that function and requires investigation; the prompt does not identify a particular mechanical fault.
Source: New Jersey CDL Manual, March 2025 cover; Section 7, July 2017 footer, printed 7-5, physical 100 > 7.4.1 Test Trailer Emergency Brakes. ↗
