Risk assessment is becoming increasingly popular in the filed of pavement engineering; this is primarily due to the role of the pavement manager essentially being a risk manager, whether this is in assessing the probability for premature pavement failure or in the assessment of potential for accidents due to the skid resistance properties of the pavement surface. Pavement managers can never eliminate the risk of failure or the risk to the public. The best that can be done is to manage, understand and reduce risk.

Surface friction of pavements has and always will be of extreme importance in evaluating the safety of a pavement. The FHWA1 reported that of over 25 million accidents, 19% occurred on wet pavements. For this reason it is imperative for public safety that pavement managers undertake surface friction surveys on a routine and regular basis. Furthermore, the results and meaning of the measured skid numbers must be fully understood.