  Overall, though, the list of pedestrian metros is short. It would be interesting to investigate why this is. Why aren’t there pedestrian metros in Manhattan, Boston, Shanghai, Vancouver, Paris and the City of London?

Those cities seldom, if ever, dip below 0°F in winter.

▲ dylan604 a day ago | parent [-]

They would be as effective for cities that go above 90°F as well though. Dallas has some underground tunnels that has shops/food as well as connect multiple buildings, but it's not well known unless you work in those buildings. It's not a walking town anyways, but it's not like it's advertised for avoiding the heat to those on the street.

	▲	thomassmith65 a day ago \| parent [-]
		Good point. In a city with dangerous temperatures, it's easier for neighboring property owners to reach the consensus that they need pedestrian tunnels. That makes sense when the danger is frostbite, but per your comment, also heatstroke.