i assume with the charge/assit meters, with the needle pointing in the middle is the coasting ability (since when one lets the foot off the gas, fuel injection ceases and it starts to regen... so the needle would sway to the left.... point being... hopefully one can add some gas pressure and the needle would swing towards the "assist" but a smart one would try to keep it between the two.)
also the ECO LIGHT is calibrated for the city mpg at lower speeds (27 mpg), and then calibrated for higher speeds on the highway. (32 mpg)
as for the A/C GM added a ECO button to limit A/C use if fuel efficency is a concern. (although not sure if the AC is electric or belt driven, i have a feeling that button limits the ability to stop/start if A/C is desired...)
from a test drive report one guy stopped, and the engine was killed, but as he shifted back to P the engine came back on alive and then he keyed off
from what I can tell, shifting into N does not kill the engine at all (B00!)
the engine will only be killed when the car is at absolute stopped. unlike the honda hybrids which start shutting down as you reach a lower speed. (then again as GM stated... fuel injection is ceased when throttle is not pressed)
that's it for now.