Visually based perceptions of slipperiness: underlying cues, consistency and relationship to coefficient of friction

If walkers can anticipate surface conditions, they can adjust their gait to help reduce the risk of a slip. This study investigated visual cues to slipperiness. Thirty-one participants made visually based judgements about 37 different floor surfaces. These judgements included ratings of slipperiness, reflectiveness, texture, traction, light/dark, likelihood of slipping, cautious intent as well as relative slipperiness. Correlational and regression analyses indicated that while reflectiveness is the predominant visual cue in forming judgements of slipperiness (r = 0.73; p < 0.05), texture and traction were also highly correlated with perceived slipperiness. Furthermore, participants were consistent in slipperiness judgements over time (r = 0.76; p < 0.05) and response measures and a significant relationship was observed between visual cues and coefficient of friction (COF) (r ranged from 0.16 to 0.58; all p < 0.05). Subjective ratings and measured COF, taken as a composite measure of slipperiness, may provide safety professionals with an improved indicator of 'higher risk' surface conditions. The results indicate that people rely on visual cues to judge slipperiness, that they do so consistently and that subjective ratings are related to measured COF. These results have implications for the measurement of slipperiness as well as the design of floor surfaces to be protective against slips and falls.