I call ________ on those ion/cobalt figures. My mother often goes weeks on a tank of gas, doing her 5 block commutes (with all sorts of books, papers, computer, etc., and then uses the car to go to the supermarket and other petty errands around town.
In her 97 Plymouth breeze (an obviosly heavier car), with a 2.0L SOHC engine, making 132 hp, she has not gotten less than 21 MPG, and we log and calculate every tank on every car we have had, since new.
These people who get 15.7 or 16 MPG with ecotec equipped GM economy cars must be playing boy racer around town or doing something else wrong/unresponsible. Yes, you don't get as good fuel economy around town or in traffic... No, it isnt that hard to still get decent economy, and certainly within the EPA range, even for more severe driving.
JMH