I don't know about bus stop killings but I made a connection from TX n MA to the tracking of traffic on Texas highways by monitoring bluetooth connection in vehicles. We do not use bluetooth for vehicles and keep it off on phones as we travel. Nevertheless, we suspect "they" have a workaround for this.
It is reported as a good thing to monitor the flow of traffic. But, big brother much?
This may have nothing to do with that to which Tx n Ma refers.
I think you’re confusing bluetooth connection with wifi connection. They’ve analyzed traffic by wifi traffic analogue for a long time. Bluetooth only works between the car and the phone - it’s very short range. Turn your phone off if you don’t want to be tracked. But as you say they probably have a workaround for that too.