The Chevrolet Volt has been on the roads in public hands for a year and a half now, with more than 13,000 copies sold.

Britta Gross is a GM specialist in change of infrastructure, and she made some comments at the recent EVS26 Conference on how people collectively are using their Volts.

She reported that 1 in 4 Volt drivers are managing to drive their cars exclusively on electricity.

The car can be charged at 220 or 110 Volt, and she reported that only half have opted to get the 220 V charger inside in their garages.  The charger and installation are more expensive, so many are just slow charging.

For the entire fleet overall, 60% of miles are electric only.

Nearly 1000 Volt owners have registered there cars on an independent site called Voltstats.net.  In April for example the group collectively achieved 150 mpg.

GMs official Volt tracker collecting data from all cars sold shows that over 61 million miles have been driven with nearly 37 million of those miles EV only:

http://www.chevrolet.com/volt-electric-car/

For comparison I have driven my Volt  roughly 11,000 miles with a lifetime MPG of 205, and  I use the 220 charger installed in my garage.

Reference (USA Today)