AWDs get 1-2 mpg's less than FWD's. If you keep the Edge out of the weather, then that will help your mpg's. The trips are too short to properly warm up the engine AND take advantage of the efficiency. I commuted to the bust station just like you to the train station, for years, and got penalized as a result In the ye olde days, they said that short trips like this are also hard on the engine, don't know if that still holds true with modern engine management tech & modern lubricants. Taking it easy on the gas on short trips helps too