Road Signs

Study questions with answers

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.

1. 1. 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)

2. 2. 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)

3. 3. 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)

4. 4. 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)

5. 5. 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)

6. 6. 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)

7. 7. 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)

8. 8. 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)

9. 9. 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)

10. 10. 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)

11. 11. The four-digit identification number shown for a hazardous load is preceded by which letters?

    Correct answer: The letters NA or UN

    Identification numbers used by first responders are introduced by the letters NA or UN in front of the four-digit code.

    Source: Louisiana CDL Manual, Section 2.23.3 (Lists of Regulated Products)

12. 12. What is the minimum size required for a hazardous materials placard?

    Correct answer: At least 9.8 inches (250 mm) square

    Each placard must measure at least 9.8 inches (250 mm) on a side so it is easy to read from a distance.

    Source: Louisiana CDL Manual, Section 2.23.3 (Lists of Regulated Products)