This portion of the law is regulated and enforced by the U.S. Equal Employment Opportunity Commission. Employers with 15 or more employees must comply with this law. The regulations for Title I define disability, establish guidelines for the reasonable accommodation process, address medical examinations and inquiries, and define “direct threat” when there is significant risk of substantial harm to the health or safety of the individual employee with a disability or others.  
This title prohibits private places of public accommodation from discriminating against individuals with disabilities. Examples of public accommodations include privately-owned, leased or operated facilities like hotels, restaurants, retail merchants, doctor’s offices, golf courses, private schools, day care centers, health clubs, sports stadiums, movie theaters, and so on.  This title sets the minimum standards for accessibility for alterations and new construction of facilities. It also requires public accommodations to remove barriers in existing buildings where it is easy to do so without much difficulty or expense.  This title directs businesses to make "reasonable modifications" to their usual ways of doing things when serving people with disabilities. It also requires that they take steps necessary to communicate effectively with customers with vision, hearing, and speech disabilities.  This title is regulated and enforced by the U.S. Department of Justice. 
In 1986, the National Council on Disability had recommended the enactment of an Americans with Disabilities Act (ADA) and drafted the first version of the bill which was introduced in the House and Senate in 1988. The final version of the bill was signed into law on July 26, 1990, by President George H. W. Bush. It was later amended in 2008 and signed by President George W. Bush with changes effective as of January 1, 2009.[3]
The Department of Justice may file lawsuits in federal court to enforce the ADA Compliance, and courts may order compensatory damages and back pay to remedy discrimination if the Department prevails. Under title III, the Department of Justice may also obtain civil penalties of up to $55,000 for the first violation and $110,000 for any subsequent violation of ADA Compliance.
I know there may have been concerns that the ADA may be too vague or too costly, or may lead endlessly to litigation. But I want to reassure you right now that my administration and the United States Congress have carefully crafted this Act. We've all been determined to ensure that it gives flexibility, particularly in terms of the timetable of implementation; and we've been committed to containing the costs that may be incurred.... Let the shameful wall of exclusion finally come tumbling down.[41]