How many emergency hazard triangles should be present?

The correct answer is three triangles because federal regulations require commercial vehicles to carry a set of three reflective emergency triangles. These are essential for safety, as they are used to alert other drivers in the event of a breakdown or roadside emergency. When placed correctly, these triangles can create a visible warning for approaching traffic, significantly reducing the risk of accidents.

Having only one triangle would not offer adequate visibility or warning for approaching vehicles, while two triangles would still not meet the legal requirements set forth for commercial trucks. Therefore, vehicles must be equipped with the full set of three triangles to adhere to safety standards and regulations.