What is the minimum mounting height for warning lights from the bottom of the lens?

Answer: B — 30 inches

The minimum mounting height for warning lights from the bottom of the lens is 30 inches to ensure visibility and effectiveness in a work zone. This height is specified in guidelines to provide an adequate line of sight for both vehicular and pedestrian traffic, which is crucial for safety. Mounting warning lights at this height helps to effectively grab the attention of drivers at a sufficient distance, allowing them enough time to react and adapt to changing road conditions in a work zone. By adhering to this standard, traffic control measures can be more effective in reducing accidents and ensuring that both workers and road users are safe. Lower mounting heights may reduce visibility, while heights above 30 inches may not significantly increase effectiveness and could complicate the setup unnecessarily.