Abstract: An anti-jackknifing system is provided for tractor trailers. The anti-jackknifing system includes pressure vessels mounted to the tractor for extending and retracting pins. The pins are positioned adjacent to the trailer kingpin so as to extend or retract into slots formed in plates mounted to the apron of the trailer. A controller is provided for automatically extending or retracting the pins based upon speed measurements made by a speed sensor such as the tractor's speedometer or separate GPS sensor. The controller connects to the speed sensor and pressure vessels and causes the pins to project into the race plate slots in the event that the vehicle exceeds a predetermined speed threshold and causes the pins to retract from the race plate slots in the event the vehicle has reduced its speed below a predetermined threshold.

Abstract: An anti-jackknifing system is provided for tractor trailers. The anti-jackknifing system includes pressure vessels mounted to the tractor for extending and retracting pins. The pins are positioned adjacent to the trailer kingpin so as to extend or retract into slots formed in plates mounted to the apron of the trailer. A controller is provided for automatically extending or retracting the pins based upon speed measurements made by a speed sensor such as the tractor's speedometer or separate GPS sensor. The controller connects to the speed sensor and pressure vessels and causes the pins to project into the race plate slots in the event that the vehicle exceeds a predetermined speed threshold and causes the pins to retract from the race plate slots in the event the vehicle has reduced its speed below a predetermined threshold.