Skid resistance testing from a statistical viewpoint. Paper presented at the 52nd Annual Meeting of the Highway Research Board HRB, Washington, D.C., January 1973.

Variance of skid testing data arises from the testers, test tires and pavement. The magnitude of each source is illustrated, and some of the causes are explained. The influence of the variance is examined with respect to the confidence of skid test data in repeat and survey modes. It is concluded that the reduction of variance due to the tester and the test tire will not eliminate the need for statistical methods in skid test data analysis.