50 mpg is definitely possible. I live in the D.C. area and commute about 50 miles round trip. Most of my driving is highway, but often times it is congested particularly when I drive through Washington. I estimate about 70% of my trip is highway, and 30% is city. What I notice is my to work commute averages about 41 - 43 mph, my commute home seems to average about 45 - 47. My two month running average is 43 mpg. I achieved 50.6 mpg a week ago (light traffic, few traffic lights), and my absolute best was last Friday at 51.0 mpg, both of these going home (and no I haven't hacked the computer).I live in Philly and commute to Wilmington, Delaware everyday (~60 miles round trip). My route is 95% highway and I get in the slow lane and set cruise control at 55 mph (while enjoying the antics of Howard Stern). I consistently get 50-53 miles per gallon during the week days(when I usually only use my car for my commute). When I take my car out during the weekends I do more city driving which probably drops my MPG down to around 45 MPG for the week on average.