This is a good question. I suspect that if the car is EV and you have your foot on the go pedal but you do not power it - you might see this as "0" on the power/charge meter - then maybe you're coasting. However, if the car is in HV mode, then it should be possible to actually measure this. What's difficult to ferret out is when it occurs. In the Prius PHEV, coasting - or infinite MPG - occurred at 960RPM which was the rate the ICE revolved when idling without fuel. But I've yet to find that spot on the Clarity - likely due to the difference in hybrid system and transmission.