For years, at thousands of New York City intersections, well-worn push buttons have offered harried walkers a rare promise of control over their pedestrian lives. The signs mounted above explained their purpose:

To Cross Street

Push Button

Wait for Walk Signal

Dept. of Transportation

Millions of dutiful city residents and tourists have pushed them over the years, thinking it would help speed them in their journeys. Many trusting souls might have believed they actually worked. Others, more cynical, might have suspected they were broken but pushed anyway, out of habit, or in the off chance they might bring a walk sign more quickly.

As it turns out, the cynics were right.

The city deactivated most of the pedestrian buttons long ago with the emergence of computer-controlled traffic signals, even as an unwitting public continued to push on, according to city Department of Transportation officials. More than 2,500 of the 3,250 walk buttons that still exist function essentially as mechanical placebos, city figures show. Any benefit from them is only imagined.

''I always push,'' said Réna, an employee at Long Island College Hospital in Cobble Hill, Brooklyn, who was too embarrassed to give her last name after she pushed a button on Atlantic Avenue and was told the truth. ''The sign says push, so I push. I think it works.''

Most of the buttons scattered through the city, mainly outside of Manhattan, are relics of the 1970's, before computers began tightly choreographing traffic signal patterns on major arteries. They were installed at a time when traffic was much lighter, said Michael Primeggia, deputy commissioner of traffic operations for the city's Transportation Department.