What is the pressure range for the service brake when performing the emergency spring brake test?

The correct pressure range for the service brake when performing the emergency spring brake test is indeed 20-40 psi. This range is critical for ensuring that the braking system is functioning properly. During this test, the service brake should be capable of effectively stopping the vehicle within the specified pressure range, demonstrating that the system can reliably engage even in emergency situations.

This range indicates that the air pressure is sufficient for the brakes to operate correctly without being excessively high. If the pressure were too low, as suggested in other ranges, it could cause insufficient braking force, leading to unsafe driving conditions. The proper functioning of the service brakes within this specified range is essential for the safety of both the driver and others on the road.