According to the guys installing it (I talked to them when I was out walking my dog) this was a video sensor system. The system they were replacing was from 1962. It also took a long time to install (nearly a year), so perhaps calibration and testing was an issue.

For a while it would sense pedestrians about a 1/2 block back, and then switch, and then go red again as the ped got right to the intersection.

So I have a feeling that this took a while to get just right.

It seems to be perfect now... but they still have not completed the sidewalk repairs... so it may still need some more adjustment.

Interestingly enough, this was at a rather unusual corner that has had an unprotected left turn for as long as I can remember, in an area that has large eucalyptus trees mid block along the boulevard. When the task is finished, the left turn will finally have signal lights. They also angled the lights on the minor street to aim right at the motorist... I have not seen that before, usually they are perpendicular to the street.