NEW YORK -- New York City started rationing gas Friday morning as tempers remained short, lines remained long and panic buying continued more than 10 days after a deadly superstorm stunned the infrastructure of America's largest city.

Mayor Michael Bloomberg said the shortages could last another couple of weeks and that only a quarter of the city's gas stations were open. Some had no power, and others couldn't get fuel from terminals.

"This is designed to let everybody have a fair chance," Bloomberg said of the new system, based on even-numbered and odd-numbered license plates, that lets drivers fill up every other day.

The gas lines appeared to shrink Friday. "It's a lot better," said Manhattan driver Luis Cruz said. "A couple of days ago I waited four hours. They should have done this a long time ago." The line to his station was just a block and a half long. Before Friday, some lines stretched for a mile (1.6 kilometres) or more.

Superstorm Sandy killed more than 100 people in several states, most of them in New York and New Jersey, and its damage has been estimated at up to $50 billion. That makes it the second most expensive storm in U.S. history, behind Hurricane Katrina in 2005.

White House Press Secretary Jay Carney said President Barack Obama plans to travel to New York on Thursday to view recovery efforts and meet with affected families, local officials and first. Obama visited New Jersey shortly after Sandy hit, but Mayor Bloomberg asked him not come to New York because a presidential visit would complicate recovery efforts in the city.

By Friday, the Red Cross had raised $117 million in donations and pledges for relief work across 10 states, the District of Columbia and Puerto Rico. The Salvation Army had raised $5 million online and by phone.

Red Cross Senior Vice-President Roger Lowe said it would likely be the charity's largest U.S. effort since Katrina. Salvation Army Major Darryl Leedom said the population density of the Northeast may require a response that surpasses Katrina in the number of people served and resources required.

The Red Cross said it has deployed nearly every emergency response vehicle in its fleet with 5,800 workers and volunteers. It has served more than 3.2 million meals and snacks and provided more than 110,000 shelter stays along with other charities and government agencies.

The Federal Emergency Management Agency announced Thursday that it had started to move several hundred mobile homes into New York and New Jersey for the tens of thousands who have to leave their damaged homes as winter weather arrives.

The Energy Department has said the superstorm also left more people in the dark than any other storm in U.S. history. At the peak, more than 8.5 million homes and businesses across 21 states lost power.

Hundreds of thousands of customers, mostly in New York and New Jersey, were still waiting Friday for their electricity to come back on. An angry New York Gov. Andrew Cuomo blasted the local utilities as unprepared and badly managed.

"It's unacceptable the longer it goes on because the longer it goes on, people's suffering is worse," he said Thursday.

The utilities have said they are dealing with damage unprecedented in its scope.

A new, weaker storm on Wednesday dropped a layer of wet snow and knocked out power to more than 200,000 customers in New York and New Jersey, erasing some of the progress made by utility crews.

Early Friday, there were more than 288,000 outages in New York and about 265,000 in New Jersey.

The Edison Electric Institute, the industry's main lobbying group, has called restoring power in Sandy's wake the "single biggest task the utility industry has ever faced."