What do the numbers 30, 40, and 50 on the back of an Audi mean?

[MacDakota]

The numbers 30, 40, and 50 on the back of an Audi refer to the G value. It can be understood as the car's acceleration performance being 30%, 40%, and 50% of the gravitational acceleration G, respectively. The higher the number, the better the car's acceleration performance. Definition of acceleration performance: Acceleration performance refers to a car's ability to quickly increase its speed. It is generally evaluated by the car's standing start acceleration performance with continuous gear shifting and the acceleration performance in the highest and second-highest gears. Testing method for acceleration performance: The testing method for standing start acceleration performance involves placing the transmission in the starting gear, quickly starting the car with the throttle fully depressed to accelerate, and rapidly shifting gears when the engine reaches the maximum power RPM until the highest gear is engaged. The car's speed should reach over 80% of its maximum speed, with sedans reaching over 100 km/h. The shorter the standing start acceleration time (in seconds), the better the standing start acceleration performance.