During a service brake test, at what speed should you roll forward?

Rolling forward at 5 mph during a service brake test is important because it provides a realistic scenario in which the driver would be able to assess the braking performance of the vehicle. This speed is slow enough to ensure safety during the test while still allowing for adequate evaluation of brake effectiveness. At 5 mph, the driver can feel the braking response and determine whether the brakes are functioning correctly without the risk of significant momentum or hazard.

Furthermore, this speed allows for a controlled environment, making it easier to notice any improper braking actions, such as pulling to one side or an unresponsive brake pedal. Testing at higher speeds could lead to potential safety risks and may not accurately reflect how the vehicle behaves under normal driving conditions. Thus, 5 mph is considered the optimal speed for conducting thorough and safe service brake tests in a pre-trip inspection.