As the use of elevators has grown and their performance has been improved to provide safer, more dependable, and more efficient travel for passengers in multi-story buildings, so too have elevator controls been improved. The operation of the modern-day elevator is very complex, involving strict safety requirements. As a part of an elevator's equipment, the controls must accommodate several types of passenger requirements: VIP service (firefighters and medical personnel), restricted access, non-stop service, and peak demand needs. Elevator controls also need to feature modes of operation for fire response and maintenance.