HOUSTON — Thousands of residents of the nation's fourth-largest city had fled a monster storm they feared would fill their homes with water. But after Hurricane Rita spared Houston, they began heading home today, despite the urgings of officials.

Mindful of the 12-hour traffic jams during the evacuation late in the week, officials said they needed more time to restock gas stations, clear debris and restore power.

"We want to avoid traffic gridlock. So again, we can't say enough times to those I know are ready to go back to their homes: Please stay where you are," Gov. Rick Perry said.

The state homeland security director urged a staggered return of residents starting Sunday. Those who live beyond the suburbs were told, "Stay away until further notice."

But by midday, roads from Austin to Houston were clogging. Traffic picked up on I-45, the main north-south artery from Dallas to Galveston, with vehicles full of children, pillows and pets.

House Majority Leader Tom DeLay said he saw emergency relief vehicles snarled in traffic heading to Houston as he drove from his house in Sugar Land, southwest of the city, to Austin.

What the evacuees were coming home to was unclear. Stores were closed. Bank machines had no cash. Police were controlling the long lines at the few open gas stations. The Houston school district and six others in the area sustained little damage, but said they would remain closed until Wednesday to give children and teachers time to come home.

Houston's airports sustained minimal damage and most airlines serving them were expected to resume flights Sunday, spokesman Richard Fernandez said.

Mayor Bill White asked employers not to expect workers who weren't essential to getting the city up and running until Monday or Tuesday as power companies scramble to get the lights back on. About 560,000 customers in Houston and Harris County were without power.

"Frankly the fuel is not going to come as quickly as those here might like and those traveling might like," said U.S. Rep. Sheila Jackson Lee of Houston.

Jackson Lee also tried to reassure residents who feared looting like New Orleans endured in the aftermath of Katrina.

Overnight, Houston police got 28 calls and arrested 16 people for burglary, including eight at one Target store. Harris County Sheriff's Lt. John Martin said his officers arrested five people who had broken into a Wal-Mart outside the city.

"Know that your boarding up is still in place, you can be happy about that," Jackson-Lee said. "I do believe that neighborhoods are safe, so if you're worried about your possessions, your homes, the boarding is still there. But you are without power. You can go one block, there are lights, and the next block, there are no lights."

Perry called on fuel terminal owners and operators to begin refueling service stations as quickly as possible so evacuees could return home as soon as officials determine it's safe.

An assistant manager at a gas station north of Houston said drivers waiting in line were getting surly.

"People topping off creates a problem," George Brooks said as he walked around trying to explain to irritated drivers that they had to pay in advance. "Nobody is being accommodating. Our power has gone off and on, our registers have been down. People were polite yesterday, but now? Come on, folks, cut us some slack."

The mayor offered sympathetic frustration with the gas shortages, and about 200 Texas Department of Transportation trucks delivered gas to stranded motorists.

"It is just totally unacceptable that there was not adequate fuel supplies stashed around the state," White said.

In June 2001, Tropical Storm Allison drowned parts of Houston, including downtown and the Texas Medical Center, dumping up to 40 inches of rain within hours and killing 22 people.

But conditions in Houston had been largely dry before Rita brought rain and wind, leaving the city in a better position to handle the onslaught.

"There is minimal damage out there in the Houston region," said Harris County Judge Robert Eckels, the county's chief executive. "In general for a storm we have come out reasonably well."

Associated Press Writer Kristie Rieken contributed to this story.