Because of the highly developing of transportation all over the world, the transportation business requires more and more vehicles operating on the road. Therefore, the safety, especially, the one of the commercial heavy duty vehicles become the major issue in the vehicle testing. How to approach to the realest vehicle safety performance test result also becomes the social responsibility to the brake tester manufacturers. In COSBER, the German team develops C-BTT model with hydraulic loading simulation for Heavy duty vehicle to test under loading, which makes the test result more closed to the truth. While it is also equipped with two-speed motors inside to test the light duty vehicles, as well.