Walk the Line: Optimizing the Layout Design of Moving Walkways

A moving walkway (also denoted as moving sidewalk, travelator, autowalk, pedestrian conveyor, or skywalk) is a slow moving conveyor that transports standing or walking people horizontally over a short to medium distance. Constantly moving walkways have a long-lasting tradition especially inside large buildings, such as airport terminals and railway stations. Novel technological developments allow to accelerate walkways in their middle sections up to 12 km/h, while still providing a safe and much slower entrance and exit. Furthermore, first applications of moving walkways as environmentally friendly and space-efficient alternatives for urban public transport exist. In this context, our paper aims to support the layout design of moving walkways with optimization. Given a straight corridor (e.g., an airport terminal) and the passenger flows within the corridor (e.g., among gates), we aim to optimally place bidirectional walkway segments. We show that the resulting optimization problem is efficiently solvable by dynamic programming even if multiple relevant extensions, such as multiple objectives, budget constraints, and minimum safety distances, among subsequent segments are relevant. We apply our algorithm to explore the impact of constantly moving and accelerating walkways on total travel times and benchmark solutions without walkway support in a real-world case study. Our results reveal that wrongly placed walkways may considerably slow down passenger transport, but a very simple design rule leads to near-optimal results.