Page - 3 - in Maximum Tire-Road Friction Coefficient Estimation

1 Introduction 0 5 10 15 20 25 30 35 A ve ra ge Fa ta lit ie s Se rio us ly in ju re d Sl ig ht ly in ju re d Se ve re m at er ia l d am ag e (n o i nj ur y) Rain, Oil, Leaves, Loam,... Snow, Ice Figure 1.2.: Influenceofroadconditiononinjuryseverityandmaterialdamageinrelative numbers, based on [Deu12]. Two of the three road condition categories are shown; the remainder of the accidents occurred under dry road conditions. for reducing the number of accidents. 1.2. Traffic safety measures One common classification of traffic safety measures distinguishes between primary, sec- ondary and tertiary safety systems. Primary safety includes all safety systems that seek to prevent a collision or, if not possible, reduce the severity of the accident. In contrast, secondary safety includes all measures designed to reduce the injury severity for all road users involved when collision is imminent. Finally, tertiary safety refers to post-crash treatment, including measures such as first-aid education for all drivers, [Kra08, p.3]. Road traffic is determined by the complex interaction of three elements - driver, vehicle and environment. Knowledge of the friction potential can contribute on different levels of safety and road traffic elements, see Fig. 1.3. In primary safety, all elements are affected by the friction potential. With training, non-expert drivers can learn to estimate the road condition and the stabilisation of the vehicle on slippery roads. Car-to-x communication systems (C2x), seeSection2.2.3, and road signs that adapt to road conditions are examples of ways in which traffic safety can be improved on the environmental level. Concerning the vehicle level, the information can be used to warn the driver when the friction potential is very low (e.g. under icy or 3