Developed in the early 1990's by William English, the English XL is a device designed to measure pedestrian slip resistance. This device is small and portable and is powered by a gas burst instead of gravity. The English XL is a Variable Incidence Tribometer (VIT). The VIT unit applies force to the flooring surface, attempting to recreate the force of a human foot contacting the floor. The test foot cylinder contacts the surface in a heel-first manner, similar to the human foot. The size of the test foot is also similar to the area of heel contact in human walking.
