Congress has overwhelmingly passed new federal legislation outlawing discrimination against the physically disabled. The law addresses not only active forms of discrimination, the knowing and intentional denial of civil rights in employment or housing, but also more insidious, usually unintentional constraints on access and opportunity.

Nowhere is the problem of passive discrimination more apparent, especially to the physically disabled, than in existing buildings. Hundreds of thousands of buildings of all types and uses, both privately and publicly owned, pose challenges to people who cannot use their limbs, eyes or ears normally.

Fortunately, over the past 20 years, society's awareness and sensitivity have greatly improved. Long before the recent congressional action, legislators and officials at federal, state and municipal government levels had adopted regulations ordering "barrier-free" design for buildings serving the public. Likewise, many architects, engineers and other designers responsible for shaping buildings, streets and sidewalks have learned to be more responsive to the handicapped.

Until the 1960s, there was virtually no recognition of the need to design and build universally accessible architecture. As a student during that decade, I don't recall "accessibility" for the handicapped ever once being mentioned as a design issue in architectural school.

Indeed, there was little discussion at all about special populations -- children, the elderly, the vision- or hearing-impaired, the wheelchair-confined -- and their needs, despite these groups making up a significant portion of users of publicly accessible buildings.

Even today, building codes focus almost exclusively on safety issues such as structural soundness, minimizing the risks of fire and ensuring adequate ventilation. Thus architects and engineers mostly worry about strength and flammability of materials, locations of emergency egress corridors and fire stairs, and electrical safety. Consciously eliminating subtle, discriminatory architectural barriers is much less preoccupying.

Fortunately, mandatory design standards for the handicapped have steadily found their way into building codes, although based primarily on accommodating wheelchair movements in public spaces and buildings. Today we take many of these provisions for granted, notwithstanding some of their shortcomings.

Parking for the handicapped must be designated and located as close as possible to building entrances. Meanwhile, parking lots themselves typically are poorly designed, often lacking adequately delineated and lighted walkways between rows of cars. A person crossing a parking lot in a wheelchair is an easy, low-profile target for a car that is backing out of a parking space.

Curbs separating streets and sidewalks, always obstacles at street crossings, must now include wheelchair ramps. Likewise, where there are steps in exterior walkways, there must be an alternative pathway or bypass without steps. Often the accessible entrance is not the front entrance, forcing wheelchair-bound visitors to circumnavigate buildings, sometimes traveling great distances and negotiating formidable obstacles found in alleys or side yards. This can really feel like second-class, back-door citizenry.

Where entry doors and ground floors are elevated several steps above grade, designers may simply tack on a ramp without integrating it satisfactorily with the composition of the building's facade and entry stairs. Covered in ice or snow, such ramps can easily become impassable.

All corridors and doorways, including elevator doors, in publicly accessible buildings must be wide enough to allow unimpeded passage of a standard wheelchair.

Multistory buildings must have at least one elevator.

Public restrooms must allow for the movement of wheelchairs and provide plumbing fixtures, privacy partitions and grab bars.

Doors, corridors and bathrooms in apartments for handicapped occupants must be dimensioned and equipped appropriately.

These regulations suggest that substantial progress already has been made in legislating both awareness and action. But insensitivity remains. We still tend to lump diverse disabilities into one category, simplistically interpreting "handicapped" to mean persons in wheelchairs.

What about ambulatory people whose sight or hearing is limited, who may not have or be able to use arms and hands? How many people are unable to reach far or high enough to operate switches, adjust thermostats, open windows or change light bulbs, not to mention getting to the back corners of deep cabinets or refrigerators?

What about people who are blind in environments where essential, safety-related information is conveyed in written or iconographic form? Did you ever wonder how an unsighted person knows the color of a light signal at an intersection or knows when the "don't walk" sign is illuminated?

In Finland, crosswalk and street traffic signals include a highly audible beeper that emits a loud, continuous tone when it is safe for pedestrians to cross and an intermittent tone when traffic is flowing. This not only aids vision-impaired pedestrians, it also alerts motorists, cyclists and inattentive strollers.

Today, office buildings increasingly have elevators with controls mounted lower and with floor numbers expressed in Braille characters. This concept could be extended further out into lobbies and streets, where accessible directories could announce the names and locations of occupants of a building or names and addresses of buildings and businesses in a city block.

In recent years, industrial product designers have created user-friendly appliances, furniture, machinery, tools, controls and other devices for the physically disabled, often after careful study of the ergonomics -- human engineering -- of handicapped people. Ideally, if thoughtfully designed and well crafted, such products serve the able-bodied equally well, eliminating the need to invent something special for use only by the disabled.

Perhaps the biggest and most persistent obstacle to overcome will be the inaccessibility of many older structures not easily modified without great expense. Under grandfathering provisions, they are not obliged to comply fully with all new regulations unless they are substantially renovated.

Happily, modern technology and computers are providing new means -- remotely controlled, voice-activated switches, robotic enunciators, push-button mechanisms for operating movable devices -- to eliminate architectural impediments for those with disabilities.

Now that Congress has made removing barriers the law of the land, let's see how inventive and sensitive designers can be. Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.