A grand opening, indeed.

On its first day open for business, the Tanger at The Arches outlet center in Deer Park is proving to be a popular destination.

Traffic was snarled around the 800,000-square-foot center, with Grand Boulevard -- where there are two entrances -- a virtual parking lot.

Ken Shreyer, 38, of Brentwood, said he spent an hour on two roads just to get to Tanger to see "Kung Fu Panda" with his wife and 15-month-old son, Brent, at the Regal Cinemas.

"It took a ridiculous amount of time," Shreyer said. "I'm never coming again. I'm going to take the little guy to a movie, and I'm out of here."

Ed Blumenfeld, president of Blumenfeld Development Group, the mall's Syosset-based developer, acknowledged the traffic inconvenience faced by many shoppers.

"Today's an unusual day," Blumenfeld said Thursday afternoon from Tanger. "There's been a lot of buzz. It's testing the limits of our traffic mitigation plan, but it'll calm down after the weekend."

Blumenfeld said an accident on Commack Road contributed to the traffic problems.

Thirteen Suffolk police officers were posted on the roads around Tanger, directing traffic.

Shoppers who got there early said they did not run into traffic issues. Two shoppers from Setauket, Maureen Godfrey, 40, and her friend, Michele Motekew, 36, said they arrived at Tanger at about 10:15 a.m. and it took them about a half hour.

They went to The Christmas Tree Shop and Gap Kids. The lines were about 15 to 20 minutes long at Gap Kids, they said.

The stores "were both mobbed," Godfrey said.

At noon, an overflow parking lot at the Deer Park train station was full and customers were parking on the grass, along the curbs. Traffic was backed up on Pine Aire Drive and also Howells Road, which runs through a residential Brentwood neighborhood.

There were parking spaces available for drivers who made it to the center's parking lot, although it took one driver 20 minutes to get out of the lot in early afternoon.

About 70 stores out of about 100 were to open Thursday.

According to the developer, 4,600 parking spaces are on site and an additional 130 spots are available for mall use at the Deer Park train station, 1.4 miles away. There is shuttle service to the mall.

Concerned that there wouldn't be enough parking for shoppers expected to show up, Babylon town officials temporarily lifted parking restrictions to let motorists park on four streets near the mall.

The town board rescinded existing no-parking restrictions on Burt Drive, Jefryn Boulevard East, Jefryn Boulevard West, and Marcus Boulevard for four days, from noon Thursday until noon Monday.

"The event is expected to generate more vehicles requiring the need for parking than the premises' parking lot can accommodate," according to the resolution.

Babylon Supervisor Steven Bellone said the move was a contingency plan, necessary even though the mall will be operating below capacity when it opens.

Babylon Town and Suffolk County officials say the typical evening rush-hour crunch can expect to see a bump of about 1,400 cars per hour around the outlet center. A Huntington study puts that number even higher.

Millions of dollars in road and traffic-signal improvements already completed -- and others in the works -- are supposed to ease the swell in traffic.

Blumenfeld Development Group says it has spent more than $10 million on so-called "traffic mitigation projects" -- widening intersections and installing traffic signals along Commack Road, Grand Avenue and Corbin Road.

Blumenfeld is also reconstructing the intersection at Commack Road and the Long Island Expressway in Dix Hills -- a project expected to be complete by November.

And local and federal governments are kicking in, too. Grand Boulevard was repaved with a $1.2-million federal grant. Suffolk County plans to rebuild Bay Shore and Commack roads over the next few years. And the towns of Islip and Babylon will hold about $500,000 from Blumenfeld in trust funds earmarked as contributions to future road improvements.

Until the changes are completed, shoppers were advised to follow Tanger's recommended driving directions -- from the Long Island Expressway to the Sagtikos Parkway and west along Pine Aire Drive.

Even with many of the improvements, critics of the mall say the area simply can't handle it and the slew of other major developments recently built or in the works -- a cluster of box stores in Commack, a mixed-use development planned for the Pilgrim State site and a proposed rail-truck transfer center near the Edgewood Preserve.

"Now that it's opening, the traffic nightmare we predicted will be a reality," said Laura Mansi, president of the 4 Towns Civic Association.

David Blumenfeld, vice president of Blumenfeld Development Group, has said any development would have generated traffic -- and an industrial project would have created even more than The Arches.