Tire-road coefficient of friction is often used to estimate stopping distances and other aspects of accident reconstruction. The actual value that must be used in the calculations is often obtained from published data and sometimes measured on-site. While it depends mainly on tires, road surface, ambient conditions and speed, the effective stopping capability of a vehicle is influenced also by other parameters (car, driver, ABS, etc.). This paper presents a methodology that, exploiting data obtained with on-site measurements and/or published by technical press, allows the evaluation of the coefficient of friction and the stopping capability of a car. This is done by means of a computer program, based on a fuzzy logic approach.