Quadrasteer is an electronic four wheel steering system that gives full-size vehicles greater ease of maneuverability while driving or tugging trailers at low speeds, and improves stability, handling and control at higher speeds. Introduced by Delphi, this unique system electronically controls the direction of the rear wheels, helping shorten the turning circle on full-size vehicles, which can then maneuver as adeptly as compact cars.

The system operates in three principal phases: negative, neutral and positive. At lower speeds, the rear wheels turn in the opposite direction from the front wheels. This is the negative phase. At moderate speeds, the rear wheels remain straight or neutral. At higher speeds, the rear wheels are in the positive phase, turning in the same direction as the front wheels.

During low-speed, negative-phase towing maneuvers, the trailer follows the true vehicle path much more closely than with two-wheel steering. This makes driving with a trailer in city traffic easier. Low-speed maneuvering such as backing into a boat launch or parking a camper is also easier with Quadrasteer. When backing a trailer, the negative phase greatly improves the trailer response to steering inputs, making it easier to place the trailer into position.

At higher speeds, trailering stability is significantly enhanced. The positive rear steering phase reduces the articulation angle between the vehicle and trailer, which reduces the lateral forces applied to the rear of the vehicle by the trailer. This, in turn, reduces the yaw velocity gain and increases yaw damping of the vehicle and the trailer system. The net result is increased trailering stability, reduced trailer sway and reduced need for driver to apply corrective steering to external disturbances such as wind gusts, semi-truck passing and irregular road surfaces.

Advantages:
Completely compatible with, and enhancing to, four-wheel-drive systems, quadrasteer can be driver-selective or fully automatic, depending on the automaker's requirements.

The Quadrasteer system is designed to increase the often poor turning capabilities of large vehicles like big trucks and SUVs. Delphi says it also improves vehicle stability at high speeds and while towing a trailer.

Quadrasteer uses all four wheels, and can reduce the turn-circle diameter for a full-size pickup from 45 feet to 33.9 feet.