Driver's License Test Prep
California Practice Road Signs

A diamond-shaped sign displayed on the back of a truck tells other drivers that:

  1. A.
    The truck is oversized and needs extra clearance when passing.
  2. B.
    The truck is authorized to travel in HOV lanes.
  3. C.
    The truck may be carrying a dangerous load such as gas or explosives. Correct
The Why

The answer is "The truck may be carrying a dangerous load such as gas or explosives."

A diamond-shaped placard on a truck signals that the load may be hazardous, such as gas or explosives, and trucks carrying those loads must stop before railroad tracks. The pull toward B comes from matching the truck placard to the diamond painted on HOV-lane pavement, though the two markings share only a shape and not a meaning.

Why the others miss

The traps in the wrong answers

A. The truck is oversized and needs extra clearance when passing.

Oversize loads are marked by a rectangular yellow OVERSIZE LOAD banner, not by a diamond placard. This answer reads any attention-grabbing marker on a truck's rear as a wide-load flag, because the rectangular OVERSIZE LOAD banner is the placard most drivers have consciously noticed on the highway.

B. The truck is authorized to travel in HOV lanes.

A hazardous-load diamond placard is not an HOV-lane authorization marking. HOV lane access is set by occupancy and vehicle-category rules, not by a placard on a truck's back. This answer reads the diamond on the truck as the same diamond symbol painted on HOV-lane pavement, treating one shape as a portable version of the other.

The Rule

This question tests your knowledge of Road Signs in California. Source: California Driver Manual, "Vehicles with Hazardous Loads," p.50..

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