What is a balustrade?

A balustrade functions as a safety barrier that runs along the edge of staircases, escalators, and balconies, incorporating a series of vertical posts called balusters between a top rail and a bottom rail. In the context of escalators, the balustrade extends above the steps, serving to protect users and ensure they do not accidentally step off the side. This feature is crucial in maintaining safety for passengers in transit, as it helps to prevent falls and accidents.

Understanding balustrades in this manner highlights their structural and safety significance, particularly in elevating devices like escalators where user safety is paramount. Other options refer to different components or elements not directly related to the definition of a balustrade, reinforcing the specificity of the correct answer.