I drive 27 miles (one way) to work. 1/4 of the trip consists of surface roads, and the rest consists of Highway travel (I-75 in/out of Atlanta) with stop and go traffic. I hit quite a bit of stop and go traffic.
I take it pretty easy on my X (04' 3.0i w/ Sport Pkg), and I'm getting about 20 mpg, and I'm able to drive 6 days on a tank of gas.
I took a trip a few weekends back on the interstate the whole way (no traffic), and I got 23 mpg.
I'm very happy w/ 20mpg, as my last truck got about 15/16 mpg.
NOTE: My measurements are based on what the Board Computer (BC) is telling me...
Best Regards!