A torrent of travelers descended on roadways and transportation terminals throughout the Washington area yesterday, but authorities reported that people moved smoothly toward their holiday destinations.

Airline passengers who set out early for National, Dulles International, and Baltimore-Washington International airports expecting the worst on what is traditionally one of the busiest travel days of the year found an abundance of parking spaces, breezed through terminals, and ended up waiting hours for flights that generally departed on time.

"Today was a cakewalk. It's been a delightful difference," said Louis Sievers of Herndon as he boarded a 2:45 p.m. flight from Dulles to Boston.

The exodus began early but remained orderly at Union Station, where Amtrak ridership was expected to double or triple the daily average of 5,000 passengers out of Washington.

"That number of people could turn the station into pandemonium if you don't plan for it, but we've been planning for it for weeks, and the planning is paying off," said Amtrak spokesman John Jacobsen. Reinforced ranks of Amtrak employes channeled travelers to their gates and maintained neat parallel lines that stretched the length of the station. Standees crowded the aisles of trains up and down the northeast corridor, but the trains ran on time, Jacobsen said.

"This place is packed like sardines," said Leo Scaffoldi, who has cut hair at the Union Station Barber Shop for 15 years. "This is the busiest day I have ever seen."

Many Washingtonians appeared to stay away from work, according to Metro officials, who observed an unusually light morning commute. However, more than 3,900 passengers, twice the normal daily total, took the Metro to National Airport between 9:30 a.m. and 3 p.m., spokeswoman Marilyn Dicus said.

Roads leading into National backed up in the afternoon, but there were no unusual ground difficulties, according to airport spokesman David A. Hess.

This year, holiday travelers appeared to spread their departures over a longer period, Hess said, noting that National was exceptionally busy Friday and Tuesday.

But at 4 p.m. on the eve of Thanksgiving, as traffic through the airport neared its peak, 2,000 of the 4,777 public parking spaces remained empty, Hess said. At BWI, an electronic sign installed to reroute cars from the main terminal area to satellite lots did not flash its message: parking facilities were more than half-empty late in the day.

Travelers who remembered the crush of cars that nearly brought traffic to a standstill at Dulles last Thanksgiving were pleasantly surprised to find parking spaces within 100 yards of the main terminal late in the day. Dulles increased its parking capacity by 2,500 during the year, and 4,300 of its 11,700 spaces were unfilled at 4 p.m.

The day gave new meaning to "hurry up and wait." Julie Larivee, 21, who planned to spend Thanksgiving with her boyfriend's family in North Carolina left Front Royal, Va., with her parents at 11 a.m. anticipating a slow trip to Dulles, but I-66 was relatively free of traffic.

The Larivees arrived within an hour and spent the early afternoon waiting for her 2:44 p.m. flight.

United Airlines flights carried full planeloads out of Dulles all day, but with every position staffed at the ticket counter, lines remained short at midafternoon. American Airlines flights across the country were filled to about 70 percent of their capacity, an American spokesman said.

"It's kind of dead right now," an airline supervisor said as he surveyed the scene about 3 p.m. "The loads just never materialized."

Problems with air traffic control computers delayed flights around Los Angeles and Atlanta upwards of 40 minutes, and inclement weather disrupted flight schedules at Chicago and St. Louis, FAA spokesman Fred Farrar said. But overall, airline employes expressed relief that neither snow nor rain threw a wrench into the aviation system's hubs and spokes.

The Washington area's major arteries were not as clear as the skies. District police did not report problems, but state police throughout Virginia and Maryland reported moderate to heavy traffic. "Every road leading out of the Northern Virginia area is very heavy," a Virginia State Police dispatcher said during the evening rush hour.

According to the National Weather Service, Washington area residents can expect a warmer than normal Thanksgiving, but a cold front will bring more typical temperatures for the weekend.

Today's temperatures are expected to reach a high of about 63 degrees, with a 20 percent chance of showers. But tonight and tomorrow, the weather will turn cooler with lows between 40 and 45 degrees. No rain is expected tomorrow, when the high is expected to be 54, according to the National Weather Service.

Transportation authorities said they expect traffic to abate over the holiday and surge back toward record levels Sunday, when travelers complete their round trips. Amtrak is offering discount fares today, tomorrow and Saturday as an incentive for passengers to avoid the crunch, Jacobsen said.

The American Automobile Association predicted that 7 million people will be traveling on the road this holiday weekend on the East Coast, from Delaware to Florida. Nevertheless, more than enough will remain behind in the Washington area to clog shopping mall parking lots, said Mary Anne Reynolds, a spokeswoman for the AAA Potomac Chapter.

She predicted that traffic would be congested on all the major routes leading to large retail centers. "I think it will be grim looking for parking spaces," Reynolds said. "Smart shoppers and smart motorists should either be in parking lots of shopping centers when they open at 9 a.m. or wait till midday and head to small towns to do Christmas shopping."

"This weekend would be a great weekend to explore some of the charms of the small shops in the small towns of the Washington area," Reynolds said.

Staff writer Lynda Richardson contributed to this report.