See also Glasgow, where the megaproject did happen and the American-style M8 terminates directly in the center of the city. It's never quite caught up with good public transport options. I'd suggest trams if the massive cost and time overruns of the Edinburgh scheme hadn't put me off.

(There _is_ a subway in Glasgow, but due to tunneling difficulties and its age the trains are unusually small. It feels like a 2/3 scale model of the London Underground)