In a situation where the requirements of both a state or local building code and the 2010 ADA Standards need to be considered, the code or Standard that results in greater accessibility takes precedence. This interpretation is based on the concept of “equivalent facilitation” from section 103 of the ADA Standards which states that alternative designs, products, or technologies may be used as long as they result in substantially equivalent or greater accessibility and usability. Thus, a state or local code can be used if it contains a requirement that provides a different but greater level of accessibility than the ADA Standards.
If the use of a state or local code instead of the 2010 ADA Standard is challenged, the covered entity is responsible for defending the use of this code. The ADA accessibility requirements do not supplant or replace state or local laws that impose higher accessibility standards. The governing principal to follow when state or local codes differ from the ADA is that the one that provides the most accessibility applies.
For additional information, take a look at the following resources: