Abstract: The invention provides a supporting arrangement for a trailer that is towable by a vehicle, in which the trailer includes a tongue for connecting the trailer to the vehicle. The supporting arrangement includes a tongue jack mounted on the tongue. In a deployed position, the tongue jack vertically supports the tongue and thereby prevents contact between the tongue and the ground. In a retracted position, the supporting arrangement holds the tongue jack clear of the ground. A motion detection arrangement senses a dangerous trailer configuration, in which the tongue jack is in the deployed position and actual or potential motion of the trailer above a safe speed is present, and then activates a retraction assembly that automatically moves the tongue jack from the deployed to the retracted position upon activation of the release mechanism. A manual activation arrangement is preferably also included for allowing activation of the release mechanism by a user.