Traffic calming & ticketing needed. Repeated traffic violations at downtown intersections, stoplight after stoplight, result in traffic jams, gridlock, and incessant traffic noise due to honking: obstructing an intersection, illegal turns, etc. New York City has resolved this with "Don't Block The Box Campaign"--clearly striping intersections, and heavily fining those who flout the law, resulting in jams that disrupt traffic flow for all. Video cameras can auto-ticket offenders. Post signs to warn drivers that violations will be enforced. **Don't proceed into an intersection unless you can pass completely through.**
This happens on a daily/hourly/minute-by-minute basis during rush hours at downtown SF intersections along Kearny, Montgomery, Sansome, 2nd St, New Montgomery, Market, etc. Balancing the city budget with ticketing here could be easier than shooting fish in a barrel.
--In this photo, traffic predictably blocks Kearny/3rd Street crossing Market St through a red light; note the driver making the illegal left (on a red light) across Market onto 3rd Street as well.