Attitudes are often discussed in relation to road user behaviour for example concerning safety like violations of traffic rules or use of safety equipment or mode choice like bicycle or public transport. Frequently wrong attitudes are blamed for bad behaviour in traffic, for behaviours that increase pollution, for congestion, for risk taking etc. Also, often it is heard that if it only were possible to change attitudes great improvements of driver behaviour and traffic safety would be achieved. The connection between attitude change and improved traffic safety presumes two things. Firstly, that there exists a causal relationship between attitudes and behaviour. Secondly, that it is possible to influence attitudes of road users and that there are known measures about how to change attitudes. It is important to consider both aspects of attitudes in a discussion about attitudes and traffic safety. In the present paper we briefly present a commonly accepted view of the concept of attitude as well as introducing a model stating the relationship between attitudes and behaviours. Some results from our studies in Uppsala of different aspects of road user attitudes will be used in the present discussion. Furthermore, possibilities to change attitudes will be discussed, mainly based on results presented in the literature.