John D. Collins of Alexandria lost the use of his legs when he was a senior in high school. But he retained his sense of humor.

"There is no reason to stop doing things just because a person's in a wheelchair," says Collins, 36, admitting that when he goes square dancing, it's "a little wearing on the chair."

Suffering from a rare congenital disease that calcifies his connective tissue, making him progressively less mobile, Collins has long lobbied for an inexpensive, city-funded shuttle for the mobile-impaired -- and now he has it.

The service, called DOT for no acronymical reason, officially began operating last month, but because many potential users are still obtaining a physician's confirmation that they cannot use the regular transit system, DOT is not expected to begin brisk business until after the first of the year.

A study conducted by the city last year shows that 2,470 residents of Alexandria over the age of 16 have a disability prohibiting use of the regular mass transit.

Collins said he hopes all those people plus residents temporarily impaired will call 836-5222 for one of the taxis or specially equipped vans. For $1 they can be taken door-to-door anywhere in Alexandria.

Collins' struggle to get cheap transport for the disabled began shortly after he could no longer get around without his wheelchair. Fresh out of high school, the red-haired blue-eyed entrepreneur bought a van with a hydraulic lift, named it "Vincent" and started a company called "Van-Go."

There was such a demand for his service that he soon commanded a fleet of six vans that ran eight hours a day.

But the service was expensive. To cover the expense of the vans, drivers and insurance, Collins said a short trip to National Airport might cost as much as $30. He gave up the business in 1977, barely breaking even, and then launched a drive to force the city to sponsor an affordable transportation system for the handicapped.

As the chairman of the Access and Transport Committee, a citizens advisory committee to the City Council, Collins said he had much help working out the details of an affordable, efficient system. The biggest obstacle, the funding, was approved by the council last June. It appropriated $50,000 for the current fiscal year.

Sandy Modell, director of the DOT program, said the transit service will operate every day. It will cost passengers 50 cents to take a taxi or van one way within the city from a regular bus stop or $1 if picked up at home. She said the city reimburses the Diamond Cab Co. for the actual cost of each trip.

One of the first regular DOT patrons, Janice West, 72, said that "for fixed-income people, this is a real blessing." West, who said the arthritis in her hip "can forecast the rain better than the weatherman," said she and her 42-year-old daughter, Janice, who is stricken with cerebral palsy, plan to take more trips now that they don't have to pay full fare. "Sometimes you just want to get out and see what's going on," she said. "I'm so thrilled. Now I can afford that."