Abstract: A method of controlling the motion of a coupled tractor-trailer combination in which the tractor includes a drive train having an engine and at least one ground-engaging member driveably connected to thereto via an adjustable ratio transmission may generally include detecting whether one or more preconditions relating to motion of the tractor-trailer combination is/are occurring. The method may also include detecting whether one or more further prevailing conditions that are indicative of a likelihood of adverse vehicle motion is/are occurring. In addition, if at least one precondition and at least one further condition are occurring, the method may include effecting a control action selected from the list including activating the at least one trailer brake and/or adjusting a adjustable parameter of the drive train in order to effect controlled deceleration of the tractor-trailer combination.