# Can Bluetooth beacon be detected while it’s in motion?

I’m curious to know if smartphones can actually detect Bluetooth beacon which is in motion, say while driving. Can car A detects the beacon in car B if they pass each other?

If yes, what is the speed limit and maximum distance?

Suppose car A is moving at speed $\Delta v$ relative to car B, your wireless device has an effective range of $d$, and the two cars are initially out of communication range. Then the time you have available to connect and communicate is:
Typical passing speed might be ~10mph, and assuming your bluetooth device has the class 2 radio range of 10m, the time available is about 4.5 seconds. If we assume instead that $\Delta v = 80mph$, you have ~0.56 seconds. Whether this is enough time depends on your actual devices and the amount of data you need to send.