Just been thinking about the 19% improvement the Optimal Drive engines have given Toyota's small petrol engined cars. Some of them now have better fuel economy than the Prius, and others are very close (on the EU combined cycle). 19% improvement on the '10 Prius would be nice. But some of the Optimal Drive improvement is down to stop-start, which the Prius already has.
Not really. The best case gasoline-fueled Auris, for example, gets 52.3 miles per Imperial gallon overall, or 43.6 miles per US gallon, versus 45/50 MPG for the US Prius.
The iQ gets 67mpg according to the EU test - that's better than the Prius. Admittedly it's tiny. However the 19% improvement - if it was repeated with the '10 Prius - would be very good.
