A park release valve for a trailer vehicle having a truck and a trailer and having a pneumatic brake system, and for controlling an emergency braking modulator and/or spring-loaded brakes (108a, 108b, 108c, 108d) of the trailer, comprising: a valve housing, a moveable valve element, and a push-button attached to the valve element for moving the valve element relative to the valve housing, the valve housing comprising: - a supply port for receiving a supply pressure from the truck; - a reservoir port for connection with a trailer reservoir; - a delivery port for providing a brake pressure for at least an emergency braking modulator and/or one spring-loaded brake (108a, 108b, 108c, 108d) of the trailer; and - an exhaust port for releasing pressure to the atmosphere; and the valve element is moveable into at least three positions (V1, V2, V3), wherein - in a parking position the delivery port is in communication with the exhaust port; - in a driving position the delivery port is in communication with the supply port; and - in a release position the delivery port is in communication with the reservoir port; and wherein when the supply pressure exceeds a predetermined threshold value, switching in the release position is prohibited, characterized in that the valve element is formed as a valve spool having at least one land (20, 21, 22) and at least one valley (23, 24), wherein the valve housing defines at least a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber between the valve spool and the housing, which are selectively closable by moving the valve spool a valve housing, a moveable valve element, and a push-button attached to the valve element for moving the valve element relative to the valve housing, the valve housing comprising: - a supply port for receiving a supply pressure from the truck; - a reservoir port for connection with a trailer reservoir; - a delivery port for providing a brake pressure for at least an emergency braking modulator and/or one spring-loaded brake (108a, 108b, 108c, 108d) of the trailer; and - an exhaust port for releasing pressure to the atmosphere; and the valve element is moveable into at least three positions (V1, V2, V3), wherein - in a parking position the delivery port is in communication with the exhaust port; - in a driving position the delivery port is in communication with the supply port; and - in a release position the delivery port is in communication with the reservoir port; and wherein when the supply pressure exceeds a predetermined threshold value, switching in the release position is prohibited, characterized in that the valve element is formed as a valve spool having at least one land (20, 21, 22) and at least one valley (23, 24), wherein the valve housing defines at least a first chamber, a second chamber, a third chamber, a fourth chamber and a fifth chamber between the valve spool and the housing, which are selectively closable by moving the valve spool - a supply port for receiving a supply pressure from the truck; - a reservoir port for connection with a trailer reservoir; - a delivery port for providing a brake pressure for at least an emergency braking modulator and/or one spring-loaded brake (108a, 108b, 108c, 108d) of the trailer; and - an exhaust port for releasing pressure to the atmosphere; - in a parking position the delivery port is in communication with the exhaust port; - in a driving position the delivery port is in communication with the supply port; and - in a release position the delivery port is in communication with the reservoir port; and