[MetroMPG]

I've read that GM has had some influence with the EPA in designing the formula that will be used to rate plug-in hybrids' MPG. It's unlikely they're "fudging the results" as much as they've pushed for a formula that yields silly eye-popping numbers like this.

I agree the best approach would be a dual rating: city/hwy distance on battery power alone (plus Watt hours/mile - the car's best economy measure for electric operation) ; and city/hwy MPG with the battery depleted and generator running.

The GM marketing gurus decided that the impact of any "backlash" they'll undoubtedly face from consumers who can't get anywhere near 230 mpg in their use of the car will be much smaller than the avalanche of free marketing they're currently enjoying right now from the 230 mpg announcement.

Since the vast majority of non-"car people" will only read the headlines and don't delve into the details... it's "MISSION ACCOMPLISHED" as far as the marketers are concerned.