Does anyone know how this works in Ford EVs/hybrids? I have a PHEV CMAX and have wondered about this. I've never had an issue with people honking or getting close to rear-ending me, so I assume the lights do come on when it's decelerating rapidly.
Fusion Hybrid '18 here -- no brake lights on regen activity, just the dash icon that you can enable to see that it's regenning. It's not harsh regen at least on the full hybrid (even in Eco w/ Grade Assist enabled) until you slap it in low for engine braking.
