Crews paving a new section of the Capital Beltway as part of the Woodrow Wilson Bridge project finished their work early yesterday -- nearly a full day ahead of schedule -- and anticipated traffic jams never materialized.

But motorists shouldn't think that the worst of the roadwork is over now that part of the outer loop in Alexandria has been shifted south. Crews will be tackling a similar paving project on the Beltway's inner loop over a weekend sometime next month, said John Undeland, a project spokesman.

"In the Beltway shifting game, this is only halftime," Undeland said. "I'm really encouraging folks to not let down their guard. If we don't have people planning, it's going to be gridlock city."

Virginia transportation officials had predicted that the weekend construction, which was scheduled to wrap up at 5 a.m. today, would lead to severe backups on the Beltway and Interstate 95 and overwhelm roads as drivers searched for detours. The I-95 ramp to the outer loop was closed, and the loop was limited to a single lane between Route 1 and the Potomac River.

But dire warnings about the expected gridlock -- which were repeated in news reports, radio messages and on highway signs as far south as Georgia -- kept travelers to a minimum and traffic flowing.

"We never experienced more than a mild backup, and the reason is plain and simple: The public heard the message and heeded it," Undeland said.

Exact figures were not yet available, Undeland said, but he estimated that only one-fourth of the approximately 4,500 drivers who travel that section of the outer loop each hour on a typical Saturday afternoon ventured out during the construction.

Crews began at 8 p.m. Friday to realign the Beltway segment under South Washington Street in Alexandria, and work continued round-the-clock until the new lanes were opened at 5:50 a.m. yesterday.

The project progressed more quickly than expected because surveying of the highway, which could not be performed until the lanes were cleared of traffic Friday, revealed that less asphalt than anticipated was needed to pave the banked road, officials said.

Undeland said project officials had been operating on a "worst-case scenario," anticipating that they could need as much as 1,200 tons of asphalt. In the end, crews used about 600 tons. Asphalt is put down in four layers of about two to three inches, and each layer must cool before the next is applied.

About 10:30 a.m. yesterday, David McAlister, 34, of Alexandria took a break from his morning jog on the South Washington Street overpass and peered down at the traffic flowing on the freshly paved lanes.

"It looks really nice," McAlister called back to his friend Mark Edelson, 37, of Woodbridge.

The friends, both civil engineers with the U.S. Navy, often jog near the site and have been watching the progress. Edelson said credit should go to the workers who spent the hot, wet weekend operating heavy machinery.

"The guys working on it just had to be miserable," he said. "It's like hot-tarring a roof."

Undeland said that the temperature and rain didn't affect the paving but that workers were careful to remain hydrated. He said that although drivers stayed away, onlookers, including parents with their children, gathered on the overpass Saturday to watch the paving.

At a Shell station off northbound I-95 in Lorton, Laura Maddix, 38, stopped for gas yesterday afternoon before heading to a water park. Maddix, of Lorton, said that on Saturday, her family avoided the Beltway and took back roads when they went to a movie.

"It really sounded like a gloom-and-doom scenario," Maddix said.

Lorton resident Gary Dennis, 40, who was adding air to the tires of his pickup truck at the station, said that he's a regular on I-95 and the Beltway but that he didn't go anywhere near them this weekend. He said he plans to lie low again when the new section of the inner loop is paved in a few weeks.

"I'd rather not sit in traffic and wait if they are talking about a 15-mile backup," Dennis said. "I'd rather be sitting somewhere nice and cool."