More Sidewalk Markings

Since my last post I decided to focus on these concrete contractor markings. It really has to be a conscious decision to constantly look down at the sidewalk instead of up while walking.

I had to run an errands near 30th and Ortega and 22nd and Irving yesterday. I walked from home to both of those and back. I didn't see a single one.

What's the deal? Where did they go? Here are my theories:

There weren't that many to start with. It was just a warped kid's memory.
There were more in the Inner Sunset
They have been eradicated due to the curb cut-ins for ramps at the corners
They have been eradicated by utilities work

I had noticed one along Sunset last week, so I took my camera out and hunted these up:

This is at Santiago and Sunset:

And Pacheco and Sunset:


I think the ramp theory is most likely. These are both on the "bridle path" side of Sunset, where several intersections don't have ramps. (Edited 3/24/08 - this marking is also on the center islands and west side of Sunset)

I'm going to investigate further. My husband said he saw Lawrence Kornfield, the chief Building Inspector, talk about these and the plates and such on SFGov TV.