This street sees a lot of bike traffic, being the primary route for the majority of Caltrain bike riders - 2500 people ride Caltrain with bikes daily. It's also a primary route to a large part of SoMa with people from the Mission and Potrero hill going this way to the Embarcadero.
Previously this intersection was completely unstriped. Vehicles would set up where you see the line of cars right now, but impatient drivers would swerve out of the line and into the unmarked area that is now a marked bike lane and a right turn pocket - often without looking for the cyclists off to their right. This problem was exacerbated because some motorists would see that the cyclist had "room" to their right, of course that "room" includes 2 train tracks and getting pushed into those tracks by a swerving car is a recipe for disaster. Supposedly with CEMOF in place for Caltrain, these tracks can be paved over/removed/whatever now, but the bike lane dilineates space for the cyclists to the left of the tracks.
Of course, the first time I rode down this lane - a car did the same thing, using the bike lane as a through lane on Townsend.
V C Section 21209 Motor Vehicles and Motorized Bicycles in Bicycle Lanes
Motor Vehicles and Motorized Bicycles in Bicycle Lanes
21209. (a) No person shall drive a motor vehicle in a bicycle lane established on a roadway pursuant to Section 21207 except as follows:
(1) To park where parking is permitted.
(2) To enter or leave the roadway.
(3) To prepare for a turn within a distance of 200 feet from the intersection.
(b) This section does not prohibit the use of a motorized bicycle in a bicycle lane, pursuant to Section 21207.5, at a speed no greater than is reasonable or prudent, having due regard for visibility, traffic conditions, and the condition of the roadway surface of the bicycle lane, and in a manner which does not endanger the safety of bicyclists.
Amended Ch. 262, Stats. 1988. Effective January 1, 1989.
That day, the stripes were down but the cyclist symbol was not. I predict this lane will be utilized in this manner anyway, but the striping will help. And if it gets real bad - there are plenty of cops at the Starbucks at 8th and Townsend who we can ask to help patrol this intersection.