Free Practice Questions for NH CDL Air Brakes
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7 Job WikiSample NH CDL Air Brakes Practice Questions
Try these sample questions to review concepts for the NH CDL Air Brakes exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 204+ question experience with AI tutoring.
1During an air-pressure build-up check, which component normally supplies compressed air to the storage tanks?
2What is the role of the air compressor governor in a commercial vehicle air brake system?
3During a governor check, the reservoir gauges are rising. Around what pressure should the compressor stop pumping?
4After the governor has cut out, the driver fans the brakes to lower tank pressure. Around what pressure should the compressor begin pumping again?
5Why must compressed air storage tanks be drained regularly if equipped with manual drain valves?
6How often should manual air tank drain valves be opened to remove moisture and oil?
7A bus is equipped with an alcohol evaporator for winter operation. What air-system problem is that device intended to prevent?
8Even if an air brake system has an alcohol evaporator, what daily maintenance task is still required?
9If a failed governor lets supply-tank pressure keep climbing, which device should vent at about 150 psi to protect the system?
10At what pressure is the safety relief valve in the supply tank designed to open?
About the NH CDL Air Brakes Exam
The New Hampshire CDL Air Brakes exam is the 25-question knowledge test required by the NH DMV for commercial drivers operating vehicles equipped with air brakes. It covers Section 5 of the New Hampshire Commercial Driver's Manual: air brake components (compressor, governor, tanks, safety valve, foot valve, slack adjusters, brake chambers, S-cam foundation brakes), dual air systems, spring parking and emergency brakes, in-cab inspection procedures (static leakage, applied leakage, low air warning before pressure drops below 60 psi, spring brake pop-out at 20-45 psi), stopping distances, brake lag, and downgrade braking techniques. Independent practice by OpenExamPrep provides four-option study questions with comprehensive explanations based on the official manual and FMCSA regulations. These questions serve as an educational study aid for the written knowledge examination.
Exam sponsor: New Hampshire Division of Motor Vehicles (NH DMV). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.
Assessment
A 25-question multiple-choice knowledge examination administered by NH DMV covering Section 5 of the New Hampshire Commercial Driver's Manual. To operate air-brake vehicles without restrictions, applicants must also perform the in-cab air brake check and complete skills testing in a representative vehicle.
Time Limit
Not published by NH DMV; exams administered during standard hours (8:00 a.m. to 3:00 p.m.)
Passing Score
20 of 25 correct (80%)
Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.
Official sources
- New Hampshire Division of Motor Vehicles Commercial Driver License · Source checked 2026-10-03
- New Hampshire Commercial Driver's Manual · Source checked 2026-10-03
Our practice resources: topics covered
We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.
Air Brake System Components
Air compressor and governor operation (cut-in around 100 psi, cut-out around 125 psi), storage tanks, manual and automatic drain valves, alcohol evaporators, safety relief valve (150 psi), foot valve, foundation brakes (S-cam, wedge, disc), slack adjusters, push rods, and brake drums/shoes.
Dual Air Brake Systems
Primary (rear axle) and secondary (front/other) air systems, pressure gauges, minimum operating pressure (100 psi), and pressure build-up rate (85 to 100 psi within 45 seconds).
Emergency and Parking Brake Systems
Spring brakes held back by air pressure, automatic spring brake application (pop-out between 20 and 45 psi), parking brake push-pull controls, modulating valves, anti-compounding, and tractor protection valves.
Air Brake Inspection and Testing
Air-brake inspection: in-cab air brake checks, low air warning device activation before pressure drops below 60 psi, spring brake valve pop-out (20-45 psi), static leakage check (max 2 psi/min single, 3 psi/min combo), and applied leakage check (max 3 psi/min single, 4 psi/min combo).
Using Air Brakes on the Road
Brake lag distance (about 32 feet at 55 mph), total stopping distance, controlled braking vs stab braking, brake fade and heat on downgrades, proper gear selection, snub braking, and L and Z license restrictions.
Preparing for the NH CDL Air Brakes Exam
What You Need to Know
- Passing score: 20 of 25 correct (80%)
- Assessment: A 25-question multiple-choice knowledge examination administered by NH DMV covering Section 5 of the New Hampshire Commercial Driver's Manual. To operate air-brake vehicles without restrictions, applicants must also perform the in-cab air brake check and complete skills testing in a representative vehicle.
- Time limit: Not published by NH DMV; exams administered during standard hours (8:00 a.m. to 3:00 p.m.)
- Exam / certification fees: $20 commercial learner permit; $60 for a 5-year CDL Official sources
Using Our Practice Resources
- Work through all 204 available questions
- Review every answer and explanation
- Track weak areas and revisit them
- Use our AI tutor for tough concepts
NH CDL Air Brakes: Suggested Study Strategy
Frequently Asked Questions
Who must take the New Hampshire CDL Air Brakes knowledge test?
Any driver who wants to operate a commercial motor vehicle equipped with air brakes (including full air brakes and air-over-hydraulic brakes) must take and pass the test to avoid an L or Z restriction on their license.
What is the passing score for the New Hampshire CDL Air Brakes test?
The New Hampshire DMV Air Brakes test consists of 25 multiple-choice questions; applicants must answer at least 20 correctly (80%) to pass.
What happens if a driver fails the Air Brakes test in New Hampshire?
If an applicant fails the Air Brakes knowledge test, an L restriction (No Air Brakes) will be placed on their Commercial Learner Permit or CDL, prohibiting them from operating air-braked CMVs.
What are the acceptable leakage rates for air brake systems during an in-cab inspection?
With the engine off and brakes released (static check), air loss must not exceed 2 psi per minute for single vehicles or 3 psi per minute for combination vehicles. With the service brake fully applied, leakage must not exceed 3 psi per minute for single vehicles or 4 psi per minute for combination vehicles.
At what air pressure should the low air pressure warning buzzer activate?
The low air pressure warning buzzer and light must activate before pressure drops below 60 psi in either the primary or secondary reservoir.
Are these practice questions official New Hampshire DMV exam questions?
No. These are independent practice questions developed by OpenExamPrep based on the New Hampshire Commercial Driver's Manual and FMCSA standards. They serve as an educational study aid and are not official exam questions.