Which device measures brake performance during an inspection?

The device that measures brake performance during an inspection is a brake testing machine. This machine is specifically designed to assess how well the braking system of a vehicle functions under various conditions. It simulates real driving scenarios, allowing for the evaluation of stopping distances, brake force, and overall effectiveness of the braking system.

In contrast, a pressure gauge is typically used to measure hydraulic pressure in the brake lines, rather than assessing the performance of the brakes themselves. While a speedometer provides information related to the velocity of the vehicle, it does not directly measure brake performance during an inspection. Electronic stability control is an advanced safety feature that helps maintain vehicle stability but does not directly simulate or evaluate the braking system during an inspection. Thus, the brake testing machine is the correct choice as it provides a comprehensive assessment of brake performance.