You might note, with an eye roll, that the Smart iQ's highway mileage of 37 mpg is bested by many larger cars, including the Chevy Cruze Eco and the VW Jetta Sportwagon diesel (both rated at 42 mpg on the highway).

WSJ: 2012 Scion iQ Review: Slow, Whiny, Tiny��but Great to Park | Rumble Seat by Dan Neil

For roughly half the price of the Volt, you can get the Cruze, a car that promises better gas mileage on long highway trips, when both are running on petroleum.

WSJ: Is Chevy's Cruze Dulling the Spark of its Volt?