VEHICLE BRAKING SYSTEM

A vehicle braking system comprising a supply line which is adapted to be connected to a supply of pressurised fluid, a pressurised fluid reservoir, a parking brake actuator assembly including a brake actuator having a spring brake chamber which is operable such that the supply of pressurised fluid to the spring brake chamber causes the brake actuator to move to a brake release position and the release of pressurised fluid from the spring brake chamber causes the brake actuator to move a brake apply position, a pilot operated emergency brake apply valve with an inlet which is connected to the pressurised fluid reservoir, an outlet which is connected to the spring brake chamber by a spring brake line, and a control inlet connected to an emergency braking control line, the emergency brake apply valve being movable in accordance with the pressure at its control inlet between a first position in which its inlet is connected to its outlet and a second position in which its inlet is closed and its outlet vents to a low pressure region, there being a pressure transducer provided in the emergency braking control line, characterised in that when the supply line is pressurised, the pressure sensor is directly connected to the pressurised fluid reservoir.