Yes, providing handicap parking is required on the part of employers. The minimum number of accessible parking spaces in a parking lot depends on the total number of spaces available in the lot in question. As per the ADA, lots with fewer than 25 spaces must have one accessible parking space. There should be an additional accessible space for every 25 to 50 spaces. When this number gives above 500, the required number of accessible parking spots is 2 percent of the total number of spots. The ADA also specifies the features of and the location requirements for accessible parking spaces, which you may find in the resource linked above.