This is a great idea until grandma falls over and breaks her hip.,(reply>), How would that be any different to an ordinary lift? The cars do not move horizontally with people aboard. The move horizontally to change between shafts so that one shaft can have cars that take people up and the other shaft has cars that take people down. If a car is empty in the down shaft but there are people on a higher floor it can change shafts to go up to the floor with people waiting.<br>Multiple cars but only two shafts.