Build plugins for common doorbell or surveillance systems consumers use - Ring, Ubiquiti, Frigate, whatever - and have it look for official vehicles (cops, diplomat plates, government plates, etc). When detected, publish the data to an open database searchable by the general public that includes location, time, date, direction of travel, make, model, and occupants of vehicle.

After all, if this data is really not protected by privacy laws as the cops/Flock/Axon/etc claim, then obviously it’s in our best interest to keep such a database ourselves to track those who track us. We may not have the right of way or easements or budgets to build out a network like these corporate spooks, but an open community database could cover a wide swath pretty quickly.

Surely someone out there has the time and expertise willing to take the heat for such a project.