I’ve shared this a few times in Slack, but one of the things I like to point out to folks is that OHM accepts field-surveyed data just as much as OSM does. Whenever I go out for a walk, I stop and take photos of the sidewalk marks I encounter. This makes it a lot easier to determine the age of not only the sidewalk, but also potentially the street or houses along it.
So far the oldest sidewalk marks I’ve seen in San José are from 1909–1910.
The newest I’ve seen are from the ’90s and ’00s – but not all of them were made by the contractors.
Is anyone else here using similar markings to date neighborhoods? What are the oldest and newest marks you’ve come across?