While Posawatz wouldn't give specifics, he did say that GM is actually planning to put more information on the sticker than required by the EPA. The intention is to give consumers the data they need to make an informed decision about how much the Volt will cost them to operate. This is likely to include information about electrical energy use in charge-depleting mode, gasoline use in charge-sustaining mode, blended driving under various conditions and more. What you probably won't find is a single composite EPA number like the much-maligned 230 miles per gallon announced by GM a year ago.
GM has been sharing substantial amounts of data with EPA about the Volt's performance and will provide more going forward. OnStar's VP of business development, Nick Pudar, explained that the GM telematics division is soliciting volunteers for a data collection program to monitor vehicle usage behavior. The OnStar system would record the distance traveled along with some other data (not including location or speed) for every ignition cycle of the volunteer vehicles and transmit all that back to OnStar headquarters. The data would be aggregated to help determine representative duty cycles for vehicle use.
Some of this assorted information will be used by EPA to evolve the window sticker information over the next several years, which means the values found on the 2011 Volt will almost certainly not be the same as subsequent model years. Even after nearly four years of discussion on the Volt, the EPA still has not figured out the best solution for rating plug-in hybrids and extended range electric vehicles. Maybe a year or two of real-world use will light a fire.
[Source: General Motors]