Unfortunately Voltstats doesn't breakout Gen 1 vs Gen 2, would be nice if they did.It's such an easy question to answer. http://www.fuelly.com/car/toyota/prius?engineconfig_id=&bodytype_id=&submodel_id= versus Monthly MPG tab of https://www.voltstats.net/ and done. The Prius fleet does about 48 MPG. The Volt does about 120 (100 in winter, low 140s in summer). (Can't use Fuelly's numbers for Volt because they're just noise, and self-reported to boot. VoltStats comes right off the telemetry and it's REALLY HARD to cheat it.)
Won't matter until the Prius somehow manages to start pulling 100 MPG out of its tailpipe. And frankly, I don't think anything but the Prime ever will, and that only by working more like the Volt.Unfortunately Voltstats doesn't breakout Gen 1 vs Gen 2, would be nice if they did.