<P> The concept for ABS predates the modern systems that were introduced in the 1950s . In 1908, for example, J.E. Francis introduced his' Slip Prevention Regulator for Rail Vehicles' . </P> <P> In 1920 the French automobile and aircraft pioneer Gabriel Voisin experimented with systems that modulated the hydraulic braking pressure on his aircraft brakes to reduce the risk of tire slippage . These systems use a flywheel and valve attached to a hydraulic line that feeds the brake cylinders . The flywheel is attached to a drum that runs at the same speed as the wheel . In normal braking, the drum and flywheel should spin at the same speed . However, when a wheel slows down, then the drum would do the same, leaving the flywheel spinning at a faster rate . This causes the valve to open, allowing a small amount of brake fluid to bypass the master cylinder into a local reservoir, lowering the pressure on the cylinder and releasing the brakes . The use of the drum and flywheel meant the valve only opened when the wheel was turning . In testing, a 30% improvement in braking performance was noted, because the pilots immediately applied full brakes instead of slowly increasing pressure in order to find the skid point . An additional benefit was the elimination of burned or burst tires . </P> <P> The first patented system was created by German engineer Karl Wessel in 1928 . Wessel, however, never developed a working product and neither did Robert Bosch who produced a similar patent eight years later . </P> <P> By the early 1950s, the Dunlop Maxaret anti-skid system was in widespread aviation use in the UK, with aircraft such as the Avro Vulcan and Handley Page Victor, Vickers Viscount, Vickers Valiant, English Electric Lightning, de Havilland Comet 2c, de Havilland Sea Vixen, and later aircraft, such as the Vickers VC10, Hawker Siddeley Trident, Hawker Siddeley 125, Hawker Siddeley HS 748 and derived British Aerospace ATP, and BAC One - Eleven being fitted with Maxaret as standard . Maxaret, while reducing braking distances by up to 30% in icy or wet conditions, also increased tire life, and had the additional advantage of allowing take - offs and landings in conditions that would preclude flying at all in non-Maxaret equipped aircraft . </P>

When was the anti lock braking system invented