Which of the following is considered a low overhead clearance hazard?

A vehicle entrance door is considered a low overhead clearance hazard because it represents an area where the height above the ground may be limited, posing a risk to taller vehicles. When vehicle entrance doors are in the open position, they can become an obstacle for drivers who may not be aware of their height or that they are even present. This is especially crucial in environments such as parking garages or commercial buildings, where ensuring enough vertical space for taller vehicles is essential for safe passage.

In contrast, highway signs, roadway markings, and traffic lights are generally designed with standard clearances that accommodate most vehicle heights. They are strategically placed and often elevated well above the roadway to reduce the likelihood of interference with vehicle traffic. Thus, while signs, markings, and traffic lights serve critical functions in guiding and regulating traffic, they do not present the same level of immediate risk associated with low overhead clearance as vehicle entrance doors can.