[notahacker]

> This actually increased overall throughout and per-person speed:

Increasing the average per person speed sounds like the expected result. Not necessarily a net win if the people sufficiently motivated to exit quickly to walk (who tend to bypass queues) are slowed though.

[frosted-flakes]

They still had the option of walking though. With two parallel escalators, 3 of the 4 "lanes" were for standing and one for walking, rather than reserving two lanes for walking when few people do so.