I'm working on getting data for traffic control devices and cross walks as well as motor vehicle collisions.
Some of the challenges are that PennDOT isn't responsible for this data because Philadelphia is a first class city.
We have an "impervious surface" dataset which should help us find out where elevated foot paths and sidewalks are, however, I don't think that data includes cross-walks.
It's possible that we can launch an effort to mark cross-walks by hand using aerial photography and also classify how busy a street is.
I estimate that task being a minimum of 700 man hours of analyzing the aerial data.