Cars in the Challenge were a 2012 FOrd Focus, 2011 Toyota Prius Hybrid, 2011 Nissan Leaf and a 2011 Chevy Volt.

The route was a round trip from Chicago to Naperville.

The results:At about the halfway point, the drivers exited the expressway, compiled trip data, and switched cars, the standard test-drive procedure to make sure the driving styles are balanced. For this leg of the trip, Roz drove the Leaf. The interior is roomier than the Volt, but a little noisier. Roz did like the fact that it has "a little kick."

The 2011 Nissan Leaf was the most cost efficient to drive. At $0.11 per kilowatt-hour, the total cost was $2.40.

The Chevy Volt used $1.46 worth of electricity, and $3.33 worth of gas for a total cost of $4.79.

The Prius, which uses electricity and gasoline together, consumed $5.02 worth of gas.

And the Focus used 2.1 gallons of gas for the trip at a cost of $8.72.

Of course don't forget the inital cost of the vehicles, with the Leaf being over $30K and the Ford Focus gasoline costing only $18K.