CDL Practice Test General Knowledge: 2026 Real Questions & Guide
Don't just read the guide. Test yourself with the actual questions likely to appear on your CDL test.
CDL Practice Test General Knowledge: The 2026 Guide
Do you want to pass your exam on the first try? This guide helps you prepare for the cdl practice test general knowledge section.
This test is the "Gatekeeper" for every new commercial driver. You cannot touch a steering wheel or get your license (CDL) permit until you pass this 50-question exam.
It covers Section 1 to Section 3 of the manual. It tests physics, law, and safety. Below are the core topics you must know.
Pillar 1: Driving Safely (60% of the Test)
This is the biggest part of the exam. It focuses on two skills: controlling your vehicle and seeing hazards.
The "Distance" Formulas (Must Memorize)
You must calculate distances. Do not guess. Use the math below.
1. Following Distance Rule:
- The Formula: 1 second for every 10 feet of vehicle length (under 40 mph).
- The Speed Penalty: If going over 40 mph, add 1 extra second.
- Example: You drive a 50-foot truck at 50 mph.
- Math: (50 ft / 10 = 5 seconds) + (Over 40 mph = 1 second) = 6 Seconds Total.
2. Stopping Distance:
- The Formula: Perception Distance + Reaction Distance + Braking Distance = Total Stopping Distance.
- The Reality: At 55 mph, a heavy truck takes about 450 feet to stop.
- Empty Trucks: Empty trucks take longer to stop than loaded trucks. They bounce and have less traction.
Night Driving Rules
- High Beams: Dim them within 500 feet of an oncoming vehicle. Dim them within 500 feet when following someone.
- Overdriving Headlights: Never drive so fast that you cannot stop within the light of your headlights.
Pillar 2: Transporting Cargo (Section 3)
You are responsible for the load. This is true even if you do not touch the cargo.
Securement Rules
- Tie-down Count: Use one tie-down for every 10 feet of cargo.
- The Minimum Rule: You must have at least 2 tie-downs. This applies even to small cargo.
- Header Boards: These protect the driver if cargo shifts forward during a crash.
Inspection Intervals
Check your cargo during your pre trip inspection. Then check again:
- Before starting.
- Within the first 50 miles.
- Every 150 miles or 3 hours after that.
Pillar 3: Emergencies & HazMat
Warning Devices (Triangles)
If you stop on the road, turn on your flashers. Place triangles within 10 minutes.
- One-Way Road: 10 feet, 100 feet, and 200 feet toward traffic.
- Two-Way Road: 100 feet in front, 10 feet behind, 100 feet behind.
- Hills/Curves: Move the rear triangle back to 500 feet.
Fire Safety
- Tire Fires: Use water only for tire fires. Do not use water on gas fires.
- Touch Check: Use the back of your hand to check wheel hubs for heat.
4. General Knowledge Practice Questions (2026 Update)
The Logic: The rule is 1 second for every 10 feet. 60 feet / 10 = 6 seconds. Since you are going *under* 40 mph, you do not add the extra second.
This is a classic myth question. The liver processes alcohol at a fixed rate. Nothing but time works. Coffee just makes you a wide-awake drunk.
While 0.04% is the legal limit for a DUI conviction, any detectable amount (0.02%) is enough to get you put Out-of-Service for 24 hours. You cannot drive.
Always aim at the source (base) of the fire, not the flames. Use the "PASS" method: Pull, Aim, Squeeze, Sweep.
The Logic: You only need the 'H' endorsement if the load requires PLACARDS. If the HazMat quantity is small enough to be exempt from placarding (like small batteries or consumer goods), any CDL driver can legally haul it.
General Knowledge
The #1 starting point. Covers vehicle inspections & basic road safety rules.
Conclusion
The test is predictable. Memorize the formulas and rules above.
Good luck on your exam! Once you finish this General Knowledge guide, try our specialized tests like Air Brakes and Combination Vehicles.
Explore More Practice Tests
General Knowledge
The #1 starting point. Covers vehicle inspections & basic road safety rules.
HazMat (H)
Master the placarding tables, shipping papers, and TSA requirements.
Air Brakes (L)
Memorize critical PSI numbers and the 3-step L.A.B. check process.
Combination
Learn the 5-step coupling checklist and rollover prevention techniques.
Pass Your CDL Exam First Try
Don't guess. Practice with 1000+ real exam questions updated for 2026.
Start Free Practice
