Certain streets in SF are unspoken "highways" with timed green lights to get across the city quickly: Fell/Oak, Sutter/Bush, Geary, Lincoln Ave, 19th Ave, Guerr

Certain streets in SF are unspoken "highways" with timed green lights to get across the city quickly: Fell/Oak, Sutter/Bush, Geary, Lincoln Ave, 19th Ave, Guerrero, Howard/Folsom (though this seems to have changed with the crazy wide bike lanes). While it's completely in one's rights to ride a bike on those streets, it's pretty stupid unless you're hauling ass because the speed differential between the car and bike is too great. Urban planners can talk all they want about how these streets are bad design and cities shouldn't have them, but it's best for both parties if bikers didn't use those streets. I don't know how someone rides on those streets without thinking it's a bad idea because most of the time, it's someone on a slow mountain bike going 10 mph.