A vehicle comprises a trailer angle detection apparatus and a trailer backup control system coupled to the trailer angle detection apparatus. The trailer angle detection apparatus is configured for outputting a signal generated as a function of an angle between the vehicle and a trailer towably attached to the vehicle. The trailer backup control system includes a jackknife enabling condition detector and a jackknife counter-measures controller. The jackknife counter-measures controller alters a setting of at least one vehicle operating parameter for alleviating an adverse jackknife condition during backing of the trailer by the vehicle when the jackknife enabling condition detector determines that a jackknife enabling condition has been attained at a particular point in time during backing of the trailer by the vehicle.