Maryland CDL — General Knowledge practice
Maryland 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
12 questions · pass with 10 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 weight-limit sign posted near a bridge is based on what?
Correct answer: A bridge formula that lowers allowable weight as axles get closer together
Bridge weight-restriction signs reflect a formula that reduces the permitted axle weight when axles are spaced closely, protecting the structure.
Source: Maryland CDL Manual — Section 3.2: Weight and Balance
2. What does the round, yellow sign bearing a black railroad symbol, posted ahead of a crossing, tell a driver to do?
Correct answer: Slow down, watch and listen for a train, and be ready to stop at the tracks
The advance warning sign appears before a public crossing and signals you to reduce speed, look and listen for a train, and be prepared to halt if one is coming.
Source: Maryland CDL Manual — Section 2.15: Railroad-Highway Crossings
3. At a railroad crossing marked only with a crossbuck sign, what is a driver legally required to do?
Correct answer: Yield the right-of-way to any train using the track
A crossbuck marks the grade crossing itself and requires drivers to give way to approaching trains.
Source: Maryland CDL Manual — Section 2.15: Railroad-Highway Crossings
4. During the walk-around inspection, clearance and identification lamps and reflectors on the front of the vehicle should be what color?
Correct answer: Amber
Lamps and reflectors facing forward should be amber, while those at the rear of the vehicle should be red.
Source: Maryland CDL Manual — Section 2.1: Vehicle Inspection
5. Which emblem warns you that the vehicle ahead is a slow-moving one such as farm machinery?
Correct answer: A red triangle with an orange center
Naturally slow vehicles like tractors display a red triangular emblem with an orange middle to alert faster traffic approaching from behind.
6. How many identical placards must be shown on a vehicle that is required to be placarded for hazardous materials?
Correct answer: Four — one each on the front, rear, and both sides
A placarded load must carry at least four matching placards positioned so each of the four directions can read one.
Source: Maryland CDL Manual — Section 2.23: Hazardous Materials Rules
7. When a downgrade is posted with a 'Maximum Safe Speed' sign, how should you treat that number?
Correct answer: As the highest speed you should ever travel on that grade
A posted limit or 'Maximum Safe Speed' sign on a grade sets a ceiling you must never exceed; also heed signs showing the grade's length and steepness.
Source: Maryland CDL Manual — Section 2.16: Mountain Driving
8. A hazardous materials placard on a commercial vehicle is displayed in what shape?
Correct answer: A square turned to stand on one corner, forming a diamond
Placards are diamond-shaped and at least 9.84 inches on a side, mounted so they can be read from every side of the vehicle.
Source: Maryland CDL Manual — Section 2.23: Hazardous Materials Rules
9. On a two-lane road approaching a railroad crossing, what marking appears along with the pavement 'X'?
Correct answer: A no-passing zone marking
On two-lane roads the crossing pavement markings include a no-passing marking, and a no-passing zone sign is posted as well.
Source: Maryland CDL Manual — Section 2.15: Railroad-Highway Crossings
10. The pavement 'X' with the letters 'RR' painted on the roadway carries the same meaning as which sign?
Correct answer: The advance warning sign for a railroad crossing
The large 'X' and 'RR' markings on the pavement mean the same thing as the round advance warning sign — a crossing lies ahead.
Source: Maryland CDL Manual — Section 2.15: Railroad-Highway Crossings
11. When the red lights begin flashing at a railroad crossing, what must you do?
Correct answer: Stop, because a train is approaching and has the right-of-way
Flashing red lights mean a train is coming; stop and yield, and where there are multiple tracks be sure every track is clear before crossing.
Source: Maryland CDL Manual — Section 2.15: Railroad-Highway Crossings
12. The four-digit identification number used by first responders for a hazardous load is preceded by which letters?
Correct answer: 'NA' or 'UN'
Identification numbers begin with 'NA' or 'UN' and let emergency crews look the substance up in the Emergency Response Guidebook.
Source: Maryland CDL Manual — Section 2.23: Hazardous Materials Rules
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