This is a brief summary of how a disabled person enforces access rights under the ADA. It can get a lot more complicated:

A person is disabled if he/she has a "substantial impairment of a major life activity". A person who can’t see, walk, hear, eat, or do other fundamental tasks is disabled.

A barrier is something that prevents a disabled person from enjoying a business’ goods and services to the same extent as an able-bodied person. Many barriers have been defined in terms of weight, length, height, etc. so that there is less guesswork as to what a barrier is. For example, the access aisle of a van-accessible parking space must be 8' wide.

New buildings must be built with no barriers. Old buildings must remove barriers where it can be done without too much difficulty or expense. Ramping a step, removing a toilet partition or re-striping a parking lot are relatively cheap and easy.

When a disabled person encounters an illegal barrier, the ADA allows a lawsuit to be filed immediately. Even so, when a disabled person encounters an illegal barrier, but has not been harmed by it, I encourage the disabled person to write a letter to the business asking it to remove the barrier. When a disabled person is embarrassed, humiliated or hurt by a barrier, or the business does not respond to a letter, I file a lawsuit, seeking the removal of the barrier, money damages for my Client and attorneys’ fees.

I have my ADA expert examine the property and write a report of what needs to be done. Then some form of Settlement Conference takes place. This is where both sides hammer out a settlement of what will be fixed, how soon it will be fixed, the amount of the payment to my Client and payment of my fees.

In the usual situation, that’s all there is to it.