Main features so far :
1.The new generation will have more passenger room since it's 2.4 inches longer, 0.6 inches wider and 0.8 inches lower than the outgoing Prius.
2. 10% More efficient at 55 MPG in city.
3.The company has engineered each component of the Hybrid Synergy Drive system to be smaller and lighter, with greater energy density in the battery, and an internal-combustion engine capable of more than 40 percent thermal efficiency under some operating conditions.
4."a soon-to-be unveiled Eco model will achieve an even greater improvement" in fuel efficiency--possibly even to the rumored 60-mpg mark.