From the SFMTA FAQ:

  Why are applications required?

  Applications are required to identify locations where there are speeding concerns.

Applications seem like a very poor and slow way to identify locations when records of actual accidents, injuries and fatalities are available from police reports. Better to build where the most lives are saved, rather than where there are the most squeaky neighbors. But it's a well designed program for the purpose of shutting people up and deferring their concerns for many years.