Motorists frustrated by city gas shortages got two hopeful pieces of news that may mean their long waits in line at service stations could soon be lessened.

State officials said Tuesday that federal rules requiring clean burning gasoline will be relaxed and testing has been approved to reopen a closed pipeline that normally supplies a third of Phoenix-area's fuel.

If all goes well, the pipeline could return to normal operations by the weekend, according to both Gov. Janet Napolitano (search) and Rick Rainey, spokesman for energy company Kinder Morgan Energy Partners (search).

Motorists have been forced to drive from station to station looking for gas and to wait in lines stretching for blocks in this sprawling city with little mass transportation.

The line ruptured on July 30 near Tucson (search) and was shut down Aug. 8 as other safety concerns surfaced, causing a hiccup in the supply chain and leaving many gas stations dry since Sunday.

Napolitano also said federal officials told her they would waive rules requiring gas stations in the Phoenix area to use gasoline blended with ethanol or another additive to combat ozone pollution during the summer.

There are no gasoline refineries in Arizona, so fuel must be delivered through two pipelines operated by Kinder Morgan -- the closed one, which runs from Texas, and a second from California, which is still working.

Byron Woodson was among nearly a dozen other drivers who crowded around the islands of a Phoenix gas station Tuesday, three hours before gasoline was expected to arrive there. With an empty tank, Woodson could only leave a message for his employer saying he would likely be several hours late.

"That's what I was freaking out about," said Woodson, an administration manager at a real estate firm. "Do I have a job?"

Kim Pappas-Miller, a spokeswoman for AAA Arizona, said one gas station near downtown Phoenix was charging $3.89 a gallon; $2 a gallon prices were common elsewhere in the city.

Price spikes are a result of logged overtime and logistics, since truckers are working round-the-clock and station managers have been working for 10 days straight, said Dan Cummings, a spokesman for Arco Gas in Los Angeles.

"This domino effect started 19 days ago when the line ruptured," he said. "A normal supply will not return until you have an adequate supply coming in, and that includes both pipelines."