Indiana Air Brakes Knowledge Test CDL Practice Test
Practice with real IN Air Brakes exam questions and detailed explanations. Rated 4.8 stars by 1,000+ drivers.
Written by CDL holders and exam prep experts · Updated April 2026
Free Questions
10
Passing Score
80%
Time Limit
Typically 30 minutes; varies by testing location
Prerequisites
General Knowledge test must be completed first
What is the Air Brakes Knowledge Test Test?
The Air Brakes knowledge test is required for commercial vehicles equipped with air brake systems. Passing this test demonstrates your knowledge of air brake operation, inspection procedures, and safety protocols, and removes the 'L' restriction from your CDL.
Knowledge test to remove 'L' restriction (no air brakes) from CDL
Topic Breakdown
Air Brake System Components
~8 questions
- Compressor and reservoir systems
- Brake chambers and slack adjusters
- Air lines and fittings
Inspection and Testing
~7 questions
- Pre-trip inspection procedures
- Air pressure tests
- Brake adjustment checks
Safe Driving Practices
~6 questions
- Proper braking techniques
- Following distance requirements
- Downhill braking procedures
Emergency Procedures
~4 questions
- Air pressure loss procedures
- Emergency braking systems
- Brake failure protocols
Free Practice Questions
10 questionsQuestion 1 of 10
Why drain water from compressed air tanks?
Browse Indiana Air Brakes Questions
- 1. Why drain water from compressed air tanks?
- 2. The air brake lag distance at 55 mph on dry pavement adds about ____ feet.
- 3. What is the purpose of the modulating control valve (when equipped)?
- 4. To check the free play of manual slack adjusters of S-cam brakes, you should park on:
- 5. The spring brakes of a tractor-trailer will activate once air pressure drops to approximately:
- 6. The most common type of foundation brake found on heavy vehicles is the:
- 7. Which procedure is used in controlled braking?
- 8. Parking or emergency brakes of trucks and buses can be legally held on by ____ pressure.
- 9. A slack adjuster free play needs to be adjusted if it is more than about ____ when you pull hard on it.
- 10. Some air brake systems have an alcohol evaporator. What may happen if you don't keep the proper level of alcohol?
Study Tips for Indiana
- 1Understand the air brake system components thoroughly
- 2Practice air pressure testing procedures
- 3Memorize safe following distances
- 4Know emergency braking procedures
- 5Review state air brake regulations and inspection requirements
Indiana CDL Information
Age Requirements
Intrastate: 18+ · Interstate: 21+
CDL Renewal
Every 4 years
ELDT Required
Yes — ELDT (Entry-Level Driver Training) from FMCSA-registered provider
Indiana BMV
Official CDL Portal →Career Opportunities
Frequently Asked Questions
If you plan to drive a commercial vehicle equipped with air brakes, you must pass the air brakes knowledge test to remove the 'L' restriction from your CDL.
Air Brakes Study Resources
Be Ready for Your Indiana Air Brakes Test
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