The installation on vehicles of the so-called black box is continually spreading throughout the european car market. In Italy as many as one million vehicles are already equipped with such a device . A black box, by recording speed and position of the vehicle and, when a crash is detected, acceleration data, is mainly used by car insurance companies to monitor mileage and accidents, with the aim of reducing insurance premiums. Recently, black box producers and insurance companies are considering using acceleration data also to evaluate the stress levels car passengers can suffer during low speed accidents.The work presented here has beencarried out with the cooperation of Metasystem/OctoTelematics, a leading company in the production and management of black boxes. It investigates the possibility of evaluating cervical rachis injury risk by analyzing more than 500 acceleration curves, either in longitudinal and vertical direction, recorded by black boxes during low speed rear end accidents.As a starting point, by means of multibody numerical simulations, the parameters to describe entity and time evolution of acceleration were analyzed, also using the model proposed by McMillan for curves approximation and the most influential parameters were selected as regards injury risks. Then, by correlating such parameters with NIC (neck injury criterion), a procedure for the evaluation of rachis injury risks in the case of low speed rear end accident was developed.