How do the 2010 changes to the ADA Standards for Accessible Design impact parking spaces that already exist?

The 1991 ADA Standards require that one in eight accessible spaces be van accessible and have a 96 in. wide minimum access aisle, rather than the 60 in. wide minimum access aisle required for regular accessible spaces. The 2010 ADA Standards change that so one in six accessible spaces must be van-accessible. If the parking lot or garage is in compliance with the 1991 ADA Standards, then the “safe harbor” provision applies and the number of van accessible spaces does not have to be increased. 

If the parking lot or garage is not in compliance with the 1991 ADA Standards, it must be altered to provide accessible parking spaces in compliance with the 2010 ADA Standards if it is readily achievable to do so.

If a parking lot or garage is altered, the safe harbor provision no longer applies and more van-accessible spaces may be required.
For example: A business’ parking lot has a total of 250 parking spaces and, as required in the 1991 ADA Standards, the lot includes seven accessible parking spaces, one of which is van-accessible. The 2010 ADA Standards require two van-accessible spaces even though the total minimum number of accessible spaces remains at seven.  The business does not have to modify its parking lot to provide the additional van-accessible space until the lot undergoes a planned alteration (re-striping, re-surfacing, etc.).