Today my wife and I drove our new Mazda3 s GT 5-Door 6-Speed manual down to Boston, around the city in heavy traffic, and back home; total trip about 120 miles. Per the fuel economy app built into the main console the trip averaged 35.2 mpg. I'm fairly impressed give the following:

• With only ~250 miles on the odometer, the car/engine is far from being broken in
• Average highway speeds about 75 mph
• The A/C was running the entire time
• As mentioned above, the traffic in Boston was quite heavy
• The highway EPA ratings for the car is only 35

Will the car ever be able to return 40 mpg on a long highway trip with no A/C? Don't know for sure but I'm surely going to try.