They put powerful bluetooth sensors on poles or in roadside cabinets. They're pretty cheap to deploy so have become widely used.
Pretty much if you have two bluetooth devices talking to each other, you can be tracked by your bluetooth mac address. (Same as wifi networks and sniffing with wireshark etc)
Or if you have a device pinging with a non-random mac (ie your car).
If you've got an iphone and it's not actively being used, you get a random mac, no problems.
They put powerful bluetooth sensors on poles or in roadside cabinets. They're pretty cheap to deploy so have become widely used.
Pretty much if you have two bluetooth devices talking to each other, you can be tracked by your bluetooth mac address. (Same as wifi networks and sniffing with wireshark etc)
Or if you have a device pinging with a non-random mac (ie your car).
If you've got an iphone and it's not actively being used, you get a random mac, no problems.