The checkered line is a feature in the Mario Kart series that signifies the start of the next lap (or the start or end of the race). Depending on the course you are currently on and the game you're playing, the design of the line can change, although the basic design is still the same. Drivers should stay behind the line at all times before the race starts. The race begins once the light on the Start Signal turns green and they cross the line. If players cross the same line again after the first lap, then you'll start the next one. Cross it twice, then the final lap will begin. Cross it three times, then the race will come to an end.