An existing brake light product, the Billy light from Clearwater, integrates with the BMW canbus to pull the bike's acceleration data and use that as a basis for what this light appears to do.
I can imagine there's enough of a market for BMW accessories that they can make it work, but if you want to address other bikes with the same device, you need a different approach.
Agreed, I was more responding to the idea of tying into existing sensors or motorcycle data as noted above. The light I mentioned is part of a bigger lighting system that works through a CAN interface and has all kinds of control of settings through a somewhat convoluted overlay on existing bike inputs, like press this switch, then these, then turn the wonder wheel to adjust brightness.