There's sort of an opposite weirdness in San Francisco which is a bit ironic given where Google is located. Namely, based on various visits, Google seems very big on one taking the streetcar. Now SF streetcars are all very scenic and fun and all that but--with the possible exception of a few routes at non-crowded times of day (if there is such a thing)--useful public transportation they really aren't. (For one thing, there's often a block long line of tourists waiting to get on.)

But, yeah, it's hard. Not sure how you handle it other than just excluding streetcars from the list. (Which might not be a terrible heuristic in SF; locals feel free to disagree.)