tl;dr: Elevator scheduling has evolved from the simple SCAN/LOOK algorithms to Otis' RSR, which scores cars based on ETA, load, direction-matching, and anti-bunching, re-optimizing every 5 seconds. Benchmarks show RSR beats LOOK in most cases, but LOOK wins at high traffic or in small buildings. Counterintuitively, Destination Dispatch kiosks generally produce worse wait times than traditional up/down buttons because locking passengers to a specific car sacrifices the flexibility of continuous re-optimization.