Sources say the next Prius will also be able to run longer and faster in pure electric mode, up to a sustained 30 mph, which will significantly extend its zero-emissions range. The gains will largely come from replacing the current Prius' nickel-hydride batteries with lithium ion cells.
Lower costs for adding hybriding to cars means faster return on investment from fuel efficiency and the ability to mix several improvements at an affordable cost. $1700 for hybrid to get to 100mpg and then $100 for diesel to get to perhaps 150mpg or adding plug in options.
The hybrid center has a past and future timeline of delivered and planned hybrids
Prior plans from Honda for 65mpg+ hybrids
69 mpg diesel hybrid from Peugeot