At the same time they also couched earlier optimistic predictions and warned the traffic-crippling emergency repairs could stretch into November.

"We had no indication (of the corrosion)," Geoffrey Kolberg, the chief engineer for the Maryland Transportation Authority, said yesterday.

Engineers using ground-penetrating radar last week discovered that the internal steel U-bolts attaching the concrete Jersey walls to the eastbound span of the Bay Bridge near Kent Island were corroding. Construction, which shut down the right lane of the eastbound span yesterday, could last for up to 10 weeks, and the speed limit on that portion of the bridge will drop to 40 mph.

Commuters and beachgoers still will have three westbound lanes during morning rush hours, Sundays and Labor Day. Two-way traffic will be used as needed on the westbound span to have two eastbound lanes.

The ongoing re-decking work on the westbound span, which is unrelated to the corrosion, also will be delayed again, but officials did not know for how long.

The corrosion was discovered during inspections that followed the fatal wreck on Aug. 10, when a tractor-trailer swerved to avoid a car traveling toward it on the eastbound span, crashed into the barrier, and plunged into the water. The truck driver was killed.

Crews will attach L-shaped brackets to secure the concrete barriers to the deck and put guardrails along the walls. The temporary fix will cost $3 million.

"Our annual inspections, that go above and beyond federal requirements, confirm the Bay Bridge is safe," said John Porcari, the secretary of the state Department of Transportation.

The radar, however, is not part of the normal "hands-on" inspection process, said Cheryl Sparks, a spokesman for MdTA. The Bay Bridge is inspected every year even though federal rules require only an inspection every two years.

Corrosion on the Bay Bridge is not surprising given its proximity to water and the use of salt to melt ice during winter, said Chung C. Fu, the director of the Bridge Engineering Software and Technology Center at the University of Maryland-College Park.

"It's a very corrosive environment," he said. "The water can still go in no matter what."

But corrosion doesn't always mean imminent danger, Mr. Fu said. And the accident - a heavy tractor-trailer hitting the barrier at a direct angle - featured a tremendous level of force.

"(Corrosion) doesn't mean it will break right away," he said. "It can still protect the bridge."

Holiday traffic

For commuters who travel the Bay Bridge every day or travelers planning a leisurely Labor Day weekend, the lane closure will be another inconvenience in a long line of backups and snarling maintenance work.

"You have five lanes and hundreds of millions of dollars of taxpayer money spent and there are just non-stop repairs," said Sveinn Storm, who commutes from Centreville to his business in Annapolis. "You would think that it would work a little better … It doesn't seem right."

Motorists' tempers already were flaring yesterday, said Ivo Alviani of Kent Island, who was stuck at around 5 p.m. in the middle of the daily bridge backup.

"They should have some sort of police presence out here," he said. "People are starting to yell and honk and scream."

Transportation officials need to have a town hall meeting with local people about the problems, Mr. Alviani said.

"Personally, I don't think the (MdTA executives) drive this bridge," he said. "They don't feel the traffic and how it holds people up."

Even though the safety of Maryland drivers has to come first, closing part of the Bay Bridge before Labor Day weekend is disappointing, said Melanie Pursel, the executive director of the Ocean City Chamber of Commerce.

"Ocean City has a huge economic impact on the whole state of Maryland. You would think that the state would not want to interfere with commerce going on that weekend," she said. "We're hoping people still come because the weather has been gorgeous down here and it's been a fabulous summer."

Although Gov. Martin O'Malley's administration hopes the construction will have as little impact on traffic as possible, spokesman Rick Abbruzzese said those concerns have to be balanced with protecting drivers.

"If the engineers think this work needs to be done, then we need to do it," Mr. Abbruzzese said. "It would be irresponsible of us not to do it as quickly as possible."

Staff Writer Scott Daugherty also contributed to this report.