Saw this on Auto Express.... made me chuckle! Haven't Scientists got any thing better to do?
Don't bother polishing your car - it wastes fuel! Scientists have discovered that rough surfaces can be more aerodynamic than shiny ones by helping vehicles slip through the air more efficiently
If the bumps are the size and shape of tiny cylinders, they keep the air flowing around the car. "This goes against conventional thinking," said Swedish researcher Jens Fransson.