GM is bragging this city mileage for the Chevy Volt.

It opens a can of worms in that a true hybrid's mileage is, far more than a gasoline car, dependent on how you drive it. It's theoretically possible to get "infinite" gasoline mileage if you plug it in all the time, and only drive short distances all the time. The EPA is going to really have to work to figure out some reasonably objective method of comparing.

At least this finally explains the weird graphic on the freeway billboard: The "230" and smiling outlet seen below, with no further text. I kept trying to figure it out. A time of day? Certainly not a date (February 30??).