What is the surface of a motorcycle racing track?

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Motorcycle racing tracks have extremely high requirements for surface smoothness, with smoothness standards serving as absolute mandatory criteria, making the control of smoothness very strict. Track requirements: Each entire track must be paved with three layers of asphalt: upper, middle, and lower. The bottom layer is a 10 cm coarse asphalt concrete load-bearing layer with a smoothness of less than 8 mm; the middle layer is a 4 cm medium-grained asphalt concrete bonding layer with a smoothness of less than 5 mm; the top layer uses 4 cm modified asphalt mixture as the surface wear layer with a smoothness of less than 2 mm. Non-compliance points: For every kilometer of the laid F1 racing track, the number of non-compliance points in smoothness testing must not exceed 3, a requirement far higher than that for highways.