Which of the following describes the projection of treads that are acceptable in vehicles working over staircases?

The acceptable projection of treads for vehicles working over staircases is crucial for ensuring safety and efficiency during operations. A projection of 1-1/4 inches strikes a balance between functionality and safety, providing enough overhang to support the load while minimizing the risk of tripping or other hazards associated with substantial projections.

In the context of commercial building inspections, adhering to this standard helps maintain compliance with safety regulations and ensures that staircases function effectively as intended for both pedestrian and vehicular traffic. A lesser projection may not adequately support the vehicle or may lead to an unstable situation, while a larger projection could pose tripping hazards and complicate safe navigation up and down the stairs. Therefore, a projection of 1-1/4 inches is optimal for maintaining both safety and structural integrity when vehicles operate over stairs.