I just love this usually available landmark. Could be missing, if it's in action at a local event. It's kinda big. It's black. It can roll down the road.
If you see the Big Black Truck, grab some numbers, and use the checker. Specifically, use the US DOT seven digit number.
Or, if no Black Truck, Solve the below puzzle to obtain the keyword (7 numbers), to use in the GeoChecker.
Big Black Truck
You can validate your puzzle solution with
certitude.