Some questions: why is this pattern different for cars, where keeping the “fast lane” clear is seen essential?
The idea had come about after Len Lau, Vauxhall area manager, had gone to Hong Kong on holiday. Lau noticed that passengers on that city’s Mass Transit Railway (MTR) were standing calmly on both sides of the escalator and, it seemed, travelling more efficiently and safely as a result. His report prompted Harrison and her colleagues to wonder whether the same effect would apply at a station such as Holborn, and so they set about arranging a three-week trial.
The theory, if counterintuitive, is also pretty compelling. Think about it. It’s all very well keeping one side of the escalator clear for people in a rush, but in stations with long, steep walkways, only a small proportion are likely to be willing to climb. In lots of places, with short escalators or minimal congestion, this doesn’t much matter. But a 2002 study of escalator capacity on the Underground found that on machines such as those at Holborn, with a vertical height of 24 metres, only 40% would even contemplate it. By encouraging their preference, TfL effectively halves the capacity of the escalator in question, and creates significantly more crowding below, slowing everyone down. When you allow for the typical demands for a halo of personal space that persist in even the most disinhibited of commuters – a phenomenon described by crowd control guru Dr John J Fruin as “the human ellipse”, which means that they are largely unwilling to stand with someone directly adjacent to them or on the first step in front or behind – the theoretical capacity of the escalator halves again. Surely it was worth trying to haul back a bit of that wasted space. (Source)