Vehicle code says:

* Pedestrians -- you must stop for pedestrians who have entered a crosswalk. Pedestrians have the right of way at uncontrolled pedestrian crosswalks (i.e. those without traffic lights), but (and this is somewhat new), pedestrians can not legally just cross whenever they want -- they must wait for a safe time to try to cross. In California (as in the rest of the U.S.A.), a pedestrian crosswalk can be either explicit or implicit; quoting from the Department of Motor Vehicle's handbook, "Every intersection where streets meet at right angles has a crosswalk for pedestrians to cross the street. [...] Many pedestrian crosswalks are marked by solid white lines. Some crosswalks, especially in residential areas, are not marked."


There's not too many 'safe' times on Mission St.
Even when the traffic up ahead is stopped at a light many times the trailing cars will not stop for a pedestrian waiting at a crosswalk.