[simonsarris]

Similar in Paris. Subways cease between 1am and 5am (approx), and instead there are night busses (Noctilien)

The streets are not crowded between 1am and 5am so night busses make a lot of sense. Then of course you can do scheduled maintenance on the subways.

[tk75x]

A similar situation exists in London. When I was traveling there for school, we had Oyster cards that let us travel on the tube trains and buses but the underground transport would shut down sometime after midnight and when we stayed out late, a bus was usually available.