checkerboard flag meta racing rally start Start flag victory adrenalin beginn bike biker challenge contest course crew dangerous event getting started go line man moto motorbike motorcycle motorracing oschersleben pit crew race race line racetrack red red flag signal sport sports sportsmen starter starter's flag starters flag starting starting line waving black and white car checker checkered chequered cup fabric fabric surface finish finish line finishing formel1 formula 1 grand prix motocross object rsign speed sports race success target the end wave pattern winner winning