They're huge, and they block Muni stops, [1]and they crowd into narrow streets. And now there's another reason the city needs to get into the businesses of regulating private corporate shuttles:
The buses can get stuck on the hills.
Uptown Almanac has a great item [2], with excellent photos and a video, of a Google shuttle getting caught in Noe Valley, beached like a whale at 23rd and Chattanooga. A pickup truck tries in vain to haul the monster away.
Folks: The streets of SF's neighborhoods weren't designed for 50-foot luxury coaches. Someone's got to write some rules about where these private shuttles can go -- and where they can't.
Links:
[1] http://www.sfbg.com/2012/04/18/private-bus-problem
[2] http://uptownalmanac.com/2012/06/google-shuttle-no-match-our-hills