It has been speculated that friction variation could be a significant contributor to slip and fall incidents. However, the relationship between friction variation and a measurement of slipperiness has not been established in the literature. In this field study, the relationships among multiple friction variations, friction levels and perception ratings of slipperiness were investigated in six major working areas of 10 fast-food restaurants in the USA. The mean perception rating score for each working area was correlated with the mean friction coefficient across all the restaurants in comparison with its correlation with various friction reduction variables of each working area. The results indicated that, among 12 friction reduction variables evaluated, the absolute and relative reductions in friction over the whole working area could have a slightly better correlation with the perception rating score (r = 0.34 and 0.37, respectively) than the mean friction coefficient of each working area (0.33). However, friction variations require more effort and time to quantify than the mean friction coefficient. Furthermore, a statistically significant correlation was obtained between the maximum relative friction reduction over the whole area and the mean friction coefficient in each working area across all the restaurants evaluated (r = 0.80). The mean friction coefficient of an area is still a reasonably good indicator of slipperiness despite a slightly lower correlation with perception rating than the friction variation.