NEW YORK >> Five days before he was to start college, Fred Maahs’ world turned upside down. Off the Delaware coast in 1980, on the last day of summer vacation, the 18-year-old took a dive from his family’s boat into an unseen sandbar barely a foot below the surface, sustaining injuries that paralyzed him from the chest down.

After months of medical care, he had to find a new college to attend — the one at which he enrolled said its campus was not accessible to wheelchairs. One of his first jobs was on the second floor of a building with no elevator; two friends carried him up and down the stairs.

"For those first couple of years, I was really dependent on family or friends," said Maahs. "Back then, people with disabilities were primarily kept at home."

Were that diving accident to happen now, the campus and workplace would be accessible — with ramps, curb cuts, elevators, designated parking spots. A blind or deaf person, or anyone with a host of other disabilities, also would find accommodations enhancing their independence and engagement — all of this the legacy of the sweeping Americans with Disabilities Act, which was signed into law 25 years ago, on July 26, 1990.

"Let the shameful wall of exclusion finally come tumbling down," declared President George H. W. Bush as he prepared to sign the legislation. Some 2,000 people with disabilities — elated after years of activism — gathered outside the White House for the ceremony.

The act is monumental in scope, intended to protect people with disabilities from discrimination and enable them to participate fully in the workforce and their communities. Its protections, which now cover an estimated 55 million Americans, extend to five key areas: employment, state and local government facilities and services, public accommodations, telecommunications, and transportation.

Even before the ADA was signed, Fred Maahs was well on his way to a successful career as a businessman and disability-rights activist. He is now an executive of Comcast Corp. and recently ended a term as chairman of the American Association of People with Disabilities.

By bringing attention to physical barriers, the ADA has made "a quantum difference," he says. And yet the law — like the 1964 Civil Rights Act that helped inspire it — remains a work in progress, with some of its goals still unfulfilled.

"The unemployment rate for people with disabilities is outrageous," Maahs said. "And a law isn’t going to change the attitudinal barriers. Probably at some point in their life, every kid today with some form of disability will encounter discrimination or stereotyping or bullying."

The ADA did not come about easily — it took decades of work by people with disabilities and their allies.

In Congress, where the act was introduced in 1988, its champions included several lawmakers personally affected by disabilities, including Rep. Tony Coelho of California, who had epilepsy.

In the Senate, key supporters included Tom Harkin of Iowa, whose brother was deaf; Ted Kennedy of Massachusetts, whose son had a leg amputated, and Robert Dole of Kansas, who suffered lasting injuries during combat in Italy in World War II.

Dole, who just turned 92, recalled the staunch opposition to the bill among some of his fellow Republicans.

"Most of it was people concerned that the cost would be too great — it would put small business out of business because of what they’d have to do to comply," Dole recalled in a recent telephone interview.

Among the leading foes was Sen. Jesse Helms of North Carolina, who nicknamed the ADA the "Lawyers’ Relief Act" on the premise that it would trigger a flood of litigation. Dole and his allies argued that the ADA requirements for business were reasonable.

The bill passed the Senate by a 76-8 vote on Sept. 7, 1989, and passed the House unanimously in May.

Dole counts his work on the ADA as one of his proudest achievements. He made a tour last year across Kansas and said the crowds of well-wishers at virtually every stop included people with disabilities.

"The ADA has been a life-changer for millions for Americans," he said.

Wheelchair-accessible public transit, ATMs marked with Braille, widespread use of closed captioning, fire alarms that can be seen as well as heard — the changes brought by the ADA are apparent at every turn.

In most cases, businesses and various levels of government have made ADA-related changes as a matter of routine, at a cumulative nationwide cost running into untold billions of dollars. Just one example: It’s considered standard under ADA guidelines for accessibility compliance to add up to 20 percent to the cost of major architectural remodeling projects.

In many instances, disabled people and their lawyers have resorted to lawsuits alleging violations of the act. There have been some landmark courtroom victories, and also some complaints about overzealous lawyers shopping for disabled clients in order to file potentially lucrative suits.

A quarter-century after ADA’s passage, joblessness among disabled Americans remains far higher than for other adults. Just 17.1 percent of people with a disability were employed in 2014, compared to 64.6 percent of those without a disability, according to the latest federal figures.

The ADA stipulates that disabled job applicants should be considered on an equal basis with other applicants, but it has provided little deterrent if an employer opts not to hire a disabled person. While there have been many successful lawsuits by disabled people saying they were fired or demoted unfairly, it’s been far harder for them to win lawsuits asserting they should have been hired in the first place.

Chai Feldblum, a disability-rights lawyer who serves on the U.S. Equal Employment Opportunity Commission, said the ADA is "necessary but not sufficient" in regard to reducing unemployment. She believes progress will be made under another federal law, the Rehabilitation Act, as it applies affirmative-action targets to federal contractors so they will strive to have people with disabilities filling at least 7 percent of their jobs.