Instrument to determine the dynamic coefficient of friction COF manufacturer according to BCRA method. The instrument is a vehicle with 4 wheels composed by an aluminium chassis and a steel epoxi painted cover. A gear motor propelled by a battery Li-ION muve two wheels at 17 mm/s. The COF measure is acquired during the movement of the instrument by a slider Ø 9 mm (Four-S rubber or leather) in contact with testing surface. The vibration of the slider is transmitted to an LVDT sensor. The LVDT sensor converts the mechanical signal in a proportional electronic signal. The signal processed by an A/D microprocessor shows the medium coefficient of friction COF. At the test end the display LCD shows the medium value of COF obtained; it can be printed the diagram by the on board printer.The instrument is supplied by software running in Windows XP/Vista 7 and RS-232 output to connect a PC.