Solar-Powered Toyota Prius Project
...cool project by Canadian engineer Steve Lapp who modified his 2001 Prius by installing solar panels on the roof. It is admitted that the car is still a rough prototype, but so far the fuel economy improvement are of 10%, a respectable figure; for reference, Honda completely redesigned the Honda Civic engine for the 2006 model and achieved a 6% increase in fuel economy… Link.