A string of accidents on major roads in the Washington area snarled traffic yesterday on a day that could ill afford it.

Parts of Interstate 95, one of the East Coast's busiest highways, were closed for nearly two hours after a serious crash near Route 100 in Howard County that injured six people, two of whom were thrown from a minivan onto the roadway. Accidents then slowed traffic on thoroughfares heavy with redirected vehicles.

Transportation officials already had been bracing for problems. Home games for the Ravens, Orioles and Redskins, concerts by the Beach Boys in Timonium and Bruce Springsteen at MCI Center, and the start of Labor Day weekend caused them to take such precautions as suspending roadway construction, adding extra highway patrols and urging motorists to use alternative routes.

The crash on I-95, just north of Route 100 near Baltimore-Washington International Airport, occurred about 3 p.m. when a compact car changed lanes and collided with a Mazda MPV minivan. The van turned sharply then flipped over several times, ejecting two passengers.

The compact car ran into the median, injuring its driver.

Two infants and four adults were injured in the crash. Three helicopters took the injured to Maryland Shock Trauma Center and St. Agnes Hospital in Baltimore and Children's Hospital in the District. A 3-year-old girl from Durham, N.C., who was in the van, was reported in critical condition at Children's.

Debris from the accident scattered across the northbound lanes of I-95. Both directions of the interstate were closed, the southbound lanes for about an hour, the northbound lanes for two hours. At one point, vehicles heading north were backed up 10 miles, while traffic in the southbound lanes stretched for five miles.

As the accident unfolded, thousands of football fans were streaming from a Ravens home game at PSINet Stadium in Baltimore.

The Ravens won 28-24 on a last-second touchdown pass, which was good for the team, but not so good for traffic, as most fans stayed until the very end and left the stadium all at once.

"Traffic is flowing, but it's flowing slowly," Maryland Department of Transportation spokesman Jack Cahalan said early in yesterday's rush hour.

"We always knew we were going to have a challenge," he said. "This is just making it a bit more of a challenge."

Getting the Ravens traffic out of downtown Baltimore was crucial, not only because Friday evening rush hour was starting, but because the Orioles were set to take the field at 7:05 p.m., with fans needing to use the same parking lots filled by the Ravens game.

A Beach Boys concert at the state fairgrounds in Timonium stood to complicate traffic matters, as did a home Redskins game down I-95 in Landover, which started at 8 p.m.

Before the accident, Cahalan said: "Things had been going extremely well. We had very little difficulty whatsoever."

But the lingering delays couldn't be cleared before other incidents in and around Washington, some occurring in traffic caused by the first accident.

About 5 p.m., a crash on the northbound side of the Baltimore-Washington Parkway--which was carrying cars shunted away from the I-95 accident--closed the right lane just north of Route 198, backing traffic up to Route 50.

"That one accident really created a problem," said Ed Bowers, operations supervisor with SmarTraveler, a traffic-monitoring service. Route 29 and Route 1 were also crawling with cars, Bowers said, as motorists searched for ways around the accidents.

To help, the Maryland State Highway Administration dispatched crews to several intersections along Route 1 to coordinate signal timing, extending green lights to allow more traffic to flow north, DOT's Cahalan said.

A pair of accidents on the Capital Beltway, one at the B-W Parkway interchange and another at Kenilworth Avenue, slowed southbound I-95 traffic into the city.

Bowers said both accidents were relatively minor, but the problems they caused weren't.

"It makes for one big, long, slow ride," Bowers said.

Interstate 695, Baltimore's beltway, was a mess for a while, too, with 15 accidents and numerous disabled vehicles that had to be towed or moved to the shoulder, according to police.

"We're knee-deep in it right now," state police Sgt. Daniel Benham of the Baltimore Barracks said in the middle of the evening rush hour.

But traffic was light heading toward Camden Yards for the Orioles game, said state highway administration spokesman Dave Buck.

"It clearly does not hurt us that the team is not playing well," he said. Nonetheless, more than 41,500 fans showed up to see the Orioles lose to the Cleveland Indians, 7-6.

Farther south yesterday, delays from the accidents converged with both the end of evening rush hour and the start of traffic to the Redskins game, which drew almost 64,000 to see the home team lose to the Tampa Bay Buccaneers, 16-13.

State troopers in Prince George's County had expressed concern about traffic late at night when the Redskins game ended, the Bruce Springsteen concertgoers left MCI Center and the Washington area's Orioles fans returned from Baltimore.

But as midnight approached, traffic was reported to be moving smoothly with no major problems.

Traffic in Virginia was heavy but lacked the complications of accidents or high-capacity events, police said.

Buck, the Maryland Highway Administration spokesman, said that authorities' quick response to the original accident on I-95, plus some planning on the part of motorists who may have avoided the event-driven traffic, probably kept the congestion yesterday from being much worse.

"It sounds like people may be heeding some of the warnings," he said.