Why do escalator steps have grooves?
Short answer
The grooves mesh with comb-like parts at the landings, helping connect the moving steps to the fixed floor safely.
How it works
At the top and bottom, escalator steps become horizontal and disappear into the floor. A comb plate with many teeth is installed at each entrance and exit.
The teeth fit into the step grooves. This guides shoes from the moving step to the landing and helps keep shoes or small objects from being pulled into the boundary between them. The grooves let the two parts mesh while the steps move.
Key point
The grooves are more than a simple anti-slip pattern; they are part of a safety system. Broken or misaligned comb teeth can be dangerous, so passengers should keep away from the step edges.