> Streetcars are not usually grade-separated. Although I'd argue that unless you really need (or reasonably expect to need) the capacity of a full-scale subway

> Streetcars are not usually grade-separated. Although I'd argue that unless you really need (or reasonably expect to need) the capacity of a full-scale subway(-like) line, demanding 100 % grade-separation might again falls under the "overdesign" point: Properly done signal priority and dedicated lanes where necessary can get you quite far without requiring you to tunnel/elevate all the way or build a bridge/underpass at each crossing street.