During reconstruction of crashes involving emergency braking it is very important to determine the surface characteristics and the appropriate drag factor for the involved vehicle(s). Adequate attention may be paid to all the variables, which control vehicle/surface interaction. The variables include microtexture, macrotexture, water film depth, vehicle mass, and vehicle speed at braking. This paper uses some results from an Australian study on emergency braking stopping distance to investigate the effect of aquaplaning on crash analysis. Information from a study of the relationship between vehicle speed and onset of aquaplaning is also presented. A number of case studies are presented which illustrate how the incorrect use of skid data can seriously effect the outcome of the crash analysis.