How Many Questions Are on the CDL Test?

One of the most common questions new CDL applicants ask is simple: how many questions will I face on test day? The answer depends on which knowledge tests your state requires, but the general structure is consistent nationwide because CDL standards follow federal guidelines.

General Knowledge Test

The General Knowledge test is mandatory for every CDL applicant regardless of class. Most states present 50 questions, though the exact count can vary slightly. You typically need 80% correct—that’s 40 out of 50—to pass.

These questions cover a broad range of topics: vehicle inspection procedures, basic control of the vehicle, shifting and backing, seeing and communicating, space management, speed control, night driving, winter driving, and emergency procedures. Because the scope is wide, this test often takes the longest to prepare for.

Use a dedicated CDL General Knowledge practice test to get comfortable with the question format before your appointment.

Air Brakes Test

If the vehicle you’ll drive is equipped with air brakes—and most commercial trucks are—you must pass the Air Brakes knowledge test. This exam usually contains 25 questions, and the same 80% passing standard applies. That means you can miss no more than five questions.

Air brake questions focus on system components, inspection steps, brake lag distance, spring brakes, and what to do when pressure drops. The content is technical but manageable with focused study. Run through the CDL Air Brakes practice test repeatedly until you score well above the minimum.

Endorsement Tests

Each CDL endorsement adds a separate knowledge test with its own question count:

• Hazardous Materials (H): roughly 30 questions
• Tank Vehicles (N): roughly 20 questions
• Passenger (P): roughly 20 questions
• School Bus (S): roughly 20 questions
• Doubles/Triples (T): roughly 20 questions

You only take the endorsement tests relevant to your job. A long-haul freight driver might need Hazmat and Tanker endorsements, while a school district hire needs the School Bus test instead.

Combination Vehicles and Class-Specific Tests

Class A applicants who will operate combination vehicles typically take an additional test covering coupling, uncoupling, and safe operation of tractor-trailers. This exam is usually 20 questions. Class B drivers operating straight trucks may skip this section entirely. Some states also add a small general knowledge supplement for intrastate-only licenses, so confirm your exact test list locally.

How to Use This Information

Knowing the question count helps you set a realistic study schedule. A 50-question General Knowledge exam demands broader preparation than a focused 20-question endorsement test. Start with a full CDL practice test to see where you stand across all sections, then prioritize the areas where you fall short.

For a step-by-step approach to passing every section, combine your reading with a full CDL practice test. When you’re ready for structured practice with unlimited attempts, check out PassCDL pricing options.

---

This article is for educational purposes only. PassCDL is not affiliated with any state DMV or licensing agency.