What must be marked on the leading edge of stair treads?

The leading edge of stair treads must have a color band to ensure visibility and safety for users. This color band serves as a visual cue to indicate the point where the step begins, helping to prevent slips, trips, and falls. The contrast provided by the color band enhances the visibility of the stair edge, making it easier for individuals to navigate the stairs, especially in low-light conditions or for those with visual impairments.

While warning signs, contrast lines, or decorative patterns may contribute to safety or aesthetics in different ways, they do not specifically address the identification of the stair edge as effectively as a color band does. Therefore, marking the leading edge of stair treads with a color band is the most effective practice for enhancing safety.