A park brake module for actuating park brake cylinders (136a, 136b) of a commercial vehicle, the park brake module comprising a control port for receiving a control pressure (pC), a supply port for receiving supply pressure (pS), an exhaust, a working port for providing a brake release pressure (pBR) to the park brake cylinders (136a, 136b), a relay valve unit for receiving the control pressure (pC) and for providing the brake release pressure (pBR) to the working port dependent on the control pressure (pC), a safety port for receiving a safety pressure (pSF), a safety unit for connecting the working port to the exhaust, when the safety pressure (pSF) is supplied to the safety unit via the safety port, wherein the relay valve unit comprises a relay piston slidably arranged in a relay cylinder for performing a working stroke between an exhaust position and a fully open position, wherein the working port is in fluid communication with the exhaust when the relay piston is in the exhaust position, and wherein the brake release pressure (pBR) is provided to the working port when the relay piston is in at least a partially open position, wherein the safety unit comprises a safety piston slidably arranged in a safety cylinder for performing a safety stroke between a neutral position and a safety position, wherein the safety piston is slidable from the neutral position to the safety position by providing the safety pressure (pSF) to the safety unit, wherein the safety piston and the relay piston are operatively connected such that the relay piston is slidable between the exhaust position and the fully open position independently of the safety piston when the safety piston is in the neutral position, and such that the safety piston is configured to at least partially move the relay piston towards the exhaust position when advancing the safety position, wherein a first safety piston effective area of the safety piston is larger than a relay piston effective area of the relay piston, and wherein a first effective area ratio between the first safety piston effective area and the relay piston effective area has a value of 1.2 or larger. a control port for receiving a control pressure (pC), a supply port for receiving supply pressure (pS), an exhaust, a working port for providing a brake release pressure (pBR) to the park brake cylinders (136a, 136b), a relay valve unit for receiving the control pressure (pC) and for providing the brake release pressure (pBR) to the working port dependent on the control pressure (pC), a safety port for receiving a safety pressure (pSF), a safety unit for connecting the working port to the exhaust, when the safety pressure (pSF) is supplied to the safety unit via the safety port, wherein the relay valve unit comprises a relay piston slidably arranged in a relay cylinder for performing a working stroke between an exhaust position and a fully open position, wherein the working port is in fluid communication with the exhaust when the relay piston is in the exhaust position, and wherein the brake release pressure (pBR) is provided to the working port when the relay piston is in at least a partially open position, wherein the safety unit comprises a safety piston slidably arranged in a safety cylinder for performing a safety stroke between a neutral position and a safety position, wherein the safety piston is slidable from the neutral position to the safety position by providing the safety pressure (pSF) to the safety unit, wherein the safety piston and the relay piston are operatively connected such that the relay piston is slidable between the exhaust position and the fully open position independently of the safety piston when the safety piston is in the neutral position, and such that the safety piston is configured to at least partially move the relay piston towards the exhaust position when advancing the safety position, wherein a first safety piston effective area of the safety piston is larger than a relay piston effective area of the relay piston, and wherein a first effective area ratio between the first safety piston effective area and the relay piston effective area has a value of 1.2 or larger.