(lol, I laughed so bad when I first saw this episode)In this episode you'll notice that while Piccolo is driving like an old dude, goku is totalling cars left, right and center so I guess every time he wrecks the car he gets a new one which is not necessarily the same colour as the last ;)
That was one of my favorite episodes! Ha ha! Piccolo and Goku's car instructors really should have been switched! :) If you agree with me, then rate this helpful! :)