tl;dr: Elevator scheduling evolved from the simple SCAN/LOOK algorithms to Otis' RSR, which scores cars based on ETA, load, direction-matching, and anti-bunching, then re-optimizes every 5 seconds. Benchmarks show RSR beats LOOK at moderate traffic, but LOOK wins at high flow rates or in small buildings. Counterintuitively, Destination Dispatch kiosks—despite giving the system full trip info—generally produce worse wait times than traditional up/down buttons because locking passengers to a specific car sacrifices the flexibility that dynamic re-optimization relies on.