US 2010 ADA Standards for Accessible Design 35.151c: Title II: which standard applies and the compliance dates

What does 35.151c require?

Which standard applies depends on when physical work began: before 15 September 2010, UFAS or the 1991 Standards (the 1991 elevator exemption never applies to public entities); from 15 September 2010 through 14 March 2012, the entity may pick any of the three (2010 Standards, UFAS, 1991 Standards, again without the elevator exemption); from 15 March 2012, the 2010 Standards only. A departure from a particular requirement is permitted only where equivalent access clearly results, and work finished before 15 March 2012 that failed its standard must be fixed to the 1991 or 2010 Standards. Elements that met the 1991 Standards or UFAS enjoy a safe harbor against the program access duty of 35.150 for incremental 2010 changes until they are altered.