http://www.huffingtonpost.com/2012/0...n_1519881.html

"Speaking at an event at the Commonwealth Club of California earlier this year, San Francisco Mayor Ed Lee said his office was working in a very deliberate way with SFPD to increase enforcement of vehicular safety issues at a number of problem intersections."

Maybe that's it. Or perhaps they had more recent inspiration for a crack down on red light running cyclists...