Why can't in-service safety checks mirror new vehicle design rules? Braking performance a good example
Published May 23, 1999 by SAE Australasia in Australia
The braking ability of a vehicle is one of the most significant safety elements in automotive vehicle design today. Braking performance is critical in the avoidance of accidents and almost every single accident involves the application of the vehicle brakes. The development of improved braking systems over the years has greatly improved the vehicle safety performance and it is well documented that the number of deaths attributed to the failure of braking systems is a very small number in percentage terms in most countries of the world. Braking systems however are a contributor in nearly all accidents and therefore the performance of the vehicle brake system compared to its original design is of particular importance to regulatory authorities.
Most authorities throughout the world use brake regulations as part of their roadworthiness requirements but the type of rules and the methods used vary considerably throughout countries and even throughout States, such as in Australia and the United States. Many of these standards are based on old technologies and are considerably out of date when compared with the computerized technology and the very rapid data acquisition systems available which can provide very high levels of accuracy using modern computerized data loggers and digital sensors.
There is considerable justification for reviewing vehicle braking requirements in light of the information becoming available from the various test methods used throughout the world and in providing a more repeatable, more accurate and an easier method of database management of the existing vehicle population fleet in a country. This paper addresses the developments over time in terms of vehicle regulations, compares them with the more recent regulations covering inservice vehicle performance and identifies the discrepancies in the current system by describing a research program where a fleet of vehicles has been subject to tests under each of the methods proposed by the various regulatory authorities and the accuracies and repeatability of those test methods examined. As a result of this research program, there are good grounds for reviewing the methodology used in most countries to take advantage of the more cost- effective methods available which can be devolved down to the local garage to ensure an overall greater level of vehicle safety from braking performance than is currently available.