Well, it looks like the two keys to its success are that it's lightweight (500kg) and that it has 6 square meters of solar panel surface area. I am curious to know how they packed 6 sq m. onto a roof that's only 1 or 2 sq m.? Or maybe they used the most efficient cells available, yielding an "equivalent" of 6 sq. m. compared to some other "average" solar cell. The photos seem to suggest that the panels on the roof fold out when there is room on the road, similar to how the wings on carrier-based aircraft fold out.

It appears that little trailer thing behind it may be to provide additional solar cell surface area, as well as luggage for the long trip?

Not sure about the rooftop solar panels, but I got to see this car in person at the Street Smart Expo in San Diego in July. I must say, it is incredible how they designed it.

awesome... it uses a trailer. i've been thinking about making a lighweight car with a PV trailer.. makes sense for trying to capture sun while keeping drag down.. wheels, rails and panels vs a full brick/car

i've been thinking of incorporating a similar design into a larger scale for trucks...