[justinc8687]

Way back in the day (2010), I worked for a company using Bluetooth scanners to measure traffic speeds. We could get about a 500' range with custom hardware.

The real fun part at the time was that every Bluetooth device pretty much was always in pairing mode, and that MACs didn't rotate...

Eventually those both happened, but in ways beyond my comprehension (I worked on the software side), the hardware guys could still pick up the signals to track cars.