ENHANCED STEERING SYSTEM INSPECTION FOR IMPROVING ROAD SAFETY

Three new criteria have been developed with the purpose of improving road safety, through an enhanced wheel alignment inspection in the context of the Periodic Motor Vehicle Inspection (PMVI). Nowadays, the result of the inspection in Spain is not determined directly from an objective measurement. It depends greatly on the inspector criterion. The three developed criteria provide the inspectors with an objective procedure, based on the measuring device that is nowadays installed in the PMVI stations: the sideslip tester. The first proposed criterion checks if the toe-in angle is set according to the manufacturer's specifications, using a model that has been specifically developed to estimate this angle from the sideslip measurement. The second one evaluates if there is an excessive permanent side force when driving in straight line, thanks to a model expressly developed for this purpose. A third criterion establishes a limit for the sideslip measurement, common for all the vehicles, with a non-symmetrical range from the zero sideslip. An extensive program of validation tests has been carried out for the three proposed methods. According to them, the third proposal has been chosen as the preferred one. Previously, a comprehensive study of the sideslip measurement fundamentals and the different factors that may have an influence on the results was done.