Louisiana CDL — General Knowledge practice
Louisiana CDL — General Knowledge: Road Signs practice test
Learn the shapes, colors, and meanings of regulatory, warning, and guide signs — from stop and yield to construction and school-zone signs.
Content reviewed against official driver handbooks · August 12, 2026
14 questions · pass with 11 correct. You get instant feedback and an explanation after every answer.
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12 sample Road Signs questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.
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1. A crossbuck sign at a railroad crossing requires a driver to do what?
Correct answer: Yield the right-of-way to an approaching train
The X-shaped crossbuck marks the crossing and means you must give the right-of-way to any approaching train.
Source: Louisiana CDL Manual, Section 2.15.2 (Warning Signs and Devices)
2. A small sign mounted just below a crossbuck at a rail crossing tells you what?
Correct answer: The number of tracks at the crossing
When a crossing has more than one set of rails, a plate under the crossbuck states how many tracks there are.
Source: Louisiana CDL Manual, Section 2.15.2 (Warning Signs and Devices)
3. On the hazard class system, which class number is assigned to explosives?
Correct answer: Class 1
Explosives such as ammunition, dynamite, and fireworks make up hazard Class 1.
Source: Louisiana CDL Manual, Section 2.23.2 (Hazard Class Definitions)
4. What color should the clearance and marker lights facing forward at the front of the vehicle be?
Correct answer: Amber
Lights and reflectors that face forward at the front of the vehicle are required to be amber.
Source: Louisiana CDL Manual, Section 2.1.5 (Seven-step Inspection Method)
5. Battery fluid and hydrochloric acid are examples of which hazard class?
Correct answer: Class 8
Corrosive materials that can eat away at skin and metal, such as battery acid, fall under hazard Class 8.
Source: Louisiana CDL Manual, Section 2.23.2 (Hazard Class Definitions)
6. Which reference book do emergency responders use to match a four-digit identification number to a chemical?
Correct answer: The Emergency Response Guidebook
The U.S. DOT Emergency Response Guidebook lists chemicals and their assigned identification numbers so responders can identify a spill.
Source: Louisiana CDL Manual, Section 2.23.3 (Lists of Regulated Products)
7. What is the general shape of a hazardous materials placard displayed on the outside of a vehicle?
Correct answer: A square turned on its point, forming a diamond
Placards that identify a load's hazard class are square signs turned to stand on a point, giving them a diamond shape.
Source: Louisiana CDL Manual, Section 2.23.3 (Lists of Regulated Products)
8. A downgrade posts a sign reading 'Maximum Safe Speed.' What should you do about that number?
Correct answer: Never exceed the speed shown on the sign
A posted maximum safe speed on a grade is a limit you must never go above, and you may need to travel even slower.
Source: Louisiana CDL Manual, Section 2.16.1 (Select a Safe Speed)
9. During a walk-around inspection, what color should the reflectors and marker lights at the rear of the vehicle be?
Correct answer: Red
Reflectors and clearance/marker lights mounted at the very back of a commercial vehicle must be red.
Source: Louisiana CDL Manual, Section 2.1.5 (Seven-step Inspection Method)
10. How many identical placards must a placarded vehicle display?
Correct answer: Four, one on the front, rear, and each side
A placarded load must show four matching placards, mounted on the front, the rear, and each side so they can be read from every direction.
Source: Louisiana CDL Manual, Section 2.23.3 (Lists of Regulated Products)
11. You see a slow-moving vehicle emblem on the back of a tractor ahead. What does it look like?
Correct answer: A red triangle with an orange center
The slow-moving vehicle symbol is a reflective triangle that is red around the outside with an orange center, warning you the vehicle travels well below normal speeds.
Source: Louisiana CDL Manual, Section 2.8.3 (Drivers Who Are Hazards)
12. What is the shape and color of the advance warning sign posted ahead of a public railroad crossing?
Correct answer: A round yellow sign with black lettering
The advance warning for a grade crossing is a round sign with a yellow background and black markings; it tells you to slow, look, and listen for a train.
Source: Louisiana CDL Manual, Section 2.15.2 (Warning Signs and Devices)
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