I'm finding Projected Range to be of questionable value on our hilly New England interstates. The fundamental problem is that the system looks backwards to make its calculation in Average mode, and it varies wildly in Instant mode. The previous 5 to 30 miles may have nothing to do with what's ahead. What's needed is a system that limits energy output (perhaps via cruise control) by constantly comparing the Nav's miles-to-destination to the Rated Range, and using the delta of these two numbers to slow the car down when necessary. A user-selected safety margin (say 20 to 50 miles) would be automatically maintained. This self-correcting system would adjust for environmental and geographic factors as they occur. I'm already using this method manually. Imagine how cool it would be if the cruise control had an autopilot mode to do this for you. ADDENDUM The only missing piece is knowing, at the beginning of a trip, what your initial cruising speed should be. The drive from Boston to Burlington VT (225 miles) is relatively flat for the first hour, but if you drive too fast on that first section, the car might slow down too much toward the end of the trip in order to maintain the safety margin. Perhaps this is where Google's creativity can come into play — determining average energy usage for a particular route by taking elevation, temperature and other data into account prior to setting off.