I never try and justify any rules to any non speedway fan...the reason for this is no one ever asks. They don't care cos they follow their own sports they find interesting. if in your case you do find yourself explaining rules, then explaining your start line one they would find strange..cos I'm sure any one that doesn't follow speedway would say the same thing..which is why don't they sit stil until the tapes go up...no need to make something so simple so complicated.