I've got this from 2003;
Department of Justice Bulletin #4
(excerpt)
Products or finishes applied to surfaces after installation are not covered by ADAAG. but may fall under the Department of Justice (DOJ) regulation governing the maintenance of accessible features. Moisture and debris contamination adversely affect the surface slip resistance of most installed finishes. While floor treatments are available that will increase the coefficient of friction of a walking surface, some products or furnishings, such as furniture wax overspray or loose throw rugs, may reduce slip resistance significantly. Others-- for example, walkoff mats placed on lobby floors during rainy weather--do much to reduce the chance of slipping on a wet floor. Such mats are not considered carpets within the meaning of ADAAG 4.5.3.