They're huge, and they block Muni stops, 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 , 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.