Repeatability and bias of two walkway safety tribometers

Falls resulting from slips on walkway surfaces are a significant source of injury in society. To measure friction between the floor and the shoe, vari ous types of tribometers and ASTM standards have been developed to assess w alkway slip-resistance with the goal of improving pedestrian safety. The pu rpose of this study was to determine the repeatability and bias of the PIAS T and VIT tribometers under both dry and wet conditions. Both devices were tested on an AMTI force platform over a wide range of angles. Bias was asse ssed by comparing the tribometer slip resistance reading to the actual Fx/F z ratio measured by the force plate. while reliability was established by e valuating the ability of the tribometers to reproduce produce Fx, Fz and th e Fx/Fz ratio. Both tribometers demonstrated high degrees of bias and repea tability under both wet and dry conditions; however, each measured differen t slip-resistance values for the same surface. Further study should be dire cted at establishing which tribometer best simulates initial foot contact d uring gait with respect to measuring slip resistance.