What is one of the safety checks performed before releasing handbrakes?

One of the crucial safety checks performed before releasing handbrakes is confirming that air is built up within the brake system. This check ensures that there is sufficient air pressure for the brakes to operate correctly. In systems such as air brake systems, confirming that air pressure is built up indicates that the braking mechanism is ready and functioning properly, which is vital for maintaining control and safety of the vehicle when it begins to move. Proper air pressure signifies that the brakes can engage and function effectively when needed, preventing any potential accidents or safety hazards that could arise if the brakes fail to operate correctly due to insufficient air pressure.