On Sat, 02 Apr 2016 13:52:11 -0400, Keine Keyserscheiße
wrote:

There may be an 'instantaneous' and an 'average' which you have to designate.
--

The ones I have seen do both in separate displays. When we are
renting, I usually put it on "miles to empty". That is the one you
really need to watch out west when stations are few and far between.