I once had a simple experiment gadget thing that had a spinning black and white paddle in what looked like a light bulb. The point was that sunlight pushed on one of the coloured sides and made it spin. I think it was white that light pushed so you'll need the sun behind you to maximise your speed.
My car will be black so I'm resigned to plodding along... until I put my foot down, that is.
My car will be black so I'm resigned to plodding along... until I put my foot down, that is.