It was a strange sight to behold on a Sunday morning: the eastbound span of the Chesapeake Bay Bridge, which yearly carries tens of thousands of Washington area motorists to Maryland's Eastern shore, was bereft to all traffic.

The occasion was Maryland's third annual Bay Bridge Day wherein the public is offered the chance to leave cars behind and walk the bridge's sleek silver span from one side of the Chesapeake to the other.

The 4.04-mile walk has become a regular once-a-year event for many of the people who showed up at the bridge yesterday, despite ominous early morning weather forecasts yesterday predicting high winds, clouds and possible rain.

There were those, like Melvin and Pearl Schneider of Severn, Md., who consider the bridge walk a good occasion for a family outing. There were senior citizens like St. Claire Wellons of Rockville, age 70, who has taken the walk three times now because, she says, "I'm too old to be young, but I feel too young to be old."

There were those like Martin and Nettie Kersey of Camp Springs, who come each year, they said, simply because they like walking. And there were the philosophic types as well, like Bill Sanderson, 21, of Bethesda, who wanted to take the walk because, "I'd like to say I did it."

Most agreed they had not come for the view. Rather, they said they came for the mere pleasure of attaining a goal they had set for themselves, even if that goal was only to reach the opposite end of the bridge.

And, it was a pleasure, too, said Schneider, "for us to go across that bridge and not have to pay a toll." On all days except Bay Bridge Day, it costs a $1.25 to cross either of the bridge's two spans.

The bridge's older span, completed in 1952, was kept closed yesterday between 9 a.m. and 5 p.m. for the walk. Two-way traffic was permitted on the bridge's second span, which was opened in 1973.

It was not until 9:20 a.m., that the first group of walkers began their four-mile trek. Most had come prepared for cool weather, wearing parkas, woolen hats and gloves. The sun was at their backs and the wind against their faces.

The signs for motorists, like "Speed Limit 50" and "Do Not Stop On Bridge" seemed comically out-of-place to the walkers, whose interests were mainly in waving to the early morning boaters who passed beneath the bridge, and watching the seagulls perch on the bridge's shiny girders.

About 45 minutes into the walk, many began to drop off from the main flow of the crowd and rest a while against a railing.

"How much farther?" Margot Scowalter of Odenton shouted to a bridge policeman as she approached the first of the span's two towers.

"Two more miles . . . it's all downhill from here," the officer answered.

"Two more miles - Oh, no! Scowalter said. "Maybe my age is creeping up on me, or maybe fall isn't the best time of year to make this walk," Scowalter said. Usually, the walk is held in April. But this year it had been postponed because of bad weather.

The first of the two towers is the halfway mark on the bridge. From there the walkers could survey the wooded coves of the eastern shore, looking like thick green fingers pointing toward the water. Ahead they could see Sandy Point State Park, where the fall leaves are merely fluffs of orange, red and gold in the distance.

Though it is all downhill from the towers on, the last two miles of the walk seemed to many to be the longest.

Nevertheless, 10,000 in all made it across this year, police said.