A third type of slipperiness measuring device is an articulating arm device. It is usually a bench-top instrument that places a load on prepared samples of shoe material and floor material. A static load starts directly over the sample. A hinged bar holds the load above the material sample at the other end. The machine moves the load slowly toone side of vertical. The bar begins to form an angle from vertical. The angle of offset is increased until the shoe sample pad slides against the floor sample. Two machines of this type are the James machine4 and the NBS-Brungraber slip-resistance tester.5 There is a portable version of the NBS-Brungraber slip-resistance tester.
A more recent device is the English XL Variable Incidence Tribometer (VIT).
It is designed to provide reliable testing for wet surfaces.