1 MEASURING TYRE PERFORMANCE IN ESC INTERVENTION SITUATIONS.

Abstract – Fatal accidents during winter time in Sweden are to a large extent due to vehicle spinning. Therefore, it is crucial to analyse and compare vehicle/tyre performance on slippery roads with respect to oversteering. We have performed experimental tests to compare the stability performance of various winter tyres on ice, with and without an electronic stability system (ESC). Two different test methods are presented, one closed loop and one open loop test. Results from both studies are discussed, and it is clear that different tyres may have a large impact on vehicle stability even with ESC activated. 1. Backgr ound Active safety systems are becoming increasingly common in today’s vehicles. Electronic Stability Control (ESC) systems were introduced during the end of the 1990s, and accident statistics show that they have had a huge impact on traffic safety. Early tests on track have indicated that ESC systems have a great potential at reducing accidents where the driver suddenly lose control over the vehicle (Yamamoto and Kimura 1996). Many studies based on accident statistics confirm that ESC systems have been very effective in reducing the number of single accidents among passenger cars and SUVs. It is estimated that the introduction of ESC has decreased the number of fatal single accidents with 30-50 % for passenger cars and between 50-70 % for SUVS [1]. Some studies hav