In Sweden accidents due to loss of stability and steerability caused by braking with locked wheels to a large extent occur on icy roads in the winter. It is therefore essential that antilock systems that are expected to eliminate this type of accidents perform well under these circumstances. In order to establish suitable test methods and realistic performance levels investigations have been made both with passenger cars and commercial vehicles including heavy trailers.
Stability and steerability in terms of staying within lane boundaries with restricted steering wheel corrections and braking performance in terms of braking efficiency related to a reference performance in terms of lateral friction, locked wheel friction, optimum friction (ECE/EEC) or friction according to the ISO TR 8349 method have been considered as primary safety criteria.
These investigations are described and the results summarized. As winter performance test methods the following are discussed and recommended together with suggested minimum performance