They clutched envelopes containing the dry and official details of lives cut short: A birth or marriage certificate. A rental agreement. A letter from an employer.

The hundreds of relatives with loved ones lost in the tangled steel and concrete ruins of the World Trade Center came to the city's assistance center Wednesday to apply for death certificates — and to close a chapter.

"I just have to find a way to move on," said Barbara Sohan, who lost her 32-year-old daughter, Astrid, in the Sept. 11 attacks. "Yesterday was her birthday, and we just stayed at home. We were numb."

One police officer at the gate said some families got as far as the door but couldn't bring themselves to go through with the certificate yet.

Even though only about 300 bodies have been recovered from the wreckage, the city set up the center on a Hudson River pier to help relatives of the more than 6,300 people still missing with the process of getting death certificates.

It typically takes three years when there is no body, a delay meant to prevent fraud. But the city is reducing the wait to a few days in most cases so the victims' families can get death benefits and access bank accounts.

By the end of the first day, 297 families had started the process, aided by 120 attorneys.

"I'm still hopeful that somehow my wonderful wife will be found alive," said George Santiago, 37, his eyes brimming with tears. "But for the sake of our children, I have to somehow sort through this."

As parents, husbands and wives worked with lawyers who donated their time, about 50 family members were taken to the trade center site to leave flowers and other small memorials to the dead and missing, said Rosemarie O'Keefe, head of the city's Family Assistance Unit.

An estimated 1.2 million tons of steel, concrete and glass -- about 90 percent of the wreckage of the twin towers -- remains, according to the Army Corps of Engineers.

Security at the site is tight. A ban was added Wednesday on amateur photography of the crime scene.

Heightened security around Manhattan has snarled traffic for days. To ease the congestion, single-passenger vehicles will be banned Thursday and Friday from entering southern Manhattan from East River bridges and tunnels between 6 a.m. and noon.

Traffic was expected to be lighter Thursday because of the Jewish holiday Yom Kippur. But by 5 a.m., there were already one-hour backups at the Queensboro Bridge.

"The traffic is so bad it took me 55 minutes to go three blocks," said William Rivera, who drove alone into Manhattan from Queens a few minutes before the ban took effect.

If the restrictions work during the trial run, they could be extended, Mayor Rudolph Giuliani said Wednesday.

It's just another of the many adjustments people will have to make as they "get used to living in a different way," Giuliani said.

Police planned checkpoints to make sure drivers were carpooling, though it wasn't clear if offenders would be fined, ticketed or just turned away. The ban includes some of the busiest commuter pathways in the country.

Initially, the ban was believed to also apply to vehicles with just one person in Manhattan below 62nd Street. But the mayor, acknowledging confusion over earlier statements, clarified the restrictions during a late afternoon news conference Wednesday.

Giuliani, who has been widely praised for his steady leadership since the terrorist attacks, also said Wednesday that he would speak with his would-be successors about staying on after his term ends Dec. 31 to lead the city's recovery.

He didn't say what his role would be or how long it might last. The city charter bars the mayor from serving a third term.