A contracting global economy and a reduction in demand have driven gasoline prices lower for the third week in a row, a trend that has some experts predicting prices at the pump will be below $3 a gallon by Thanksgiving.

A gallon of regular unleaded fell about 3 cents overnight to a new national average of $3.447 a gallon yesterday, but remain well above the year-ago average of $2.765 a gallon, according to AAA and the Oil Price Information Service. Locally, area service stations were offering regular unleaded at prices ranging from $3.25 to $3.69 a gallon yesterday.

The declining prices can be traced to the fundamentals of supply and demand, said Douglas S. Haugh, executive vice president with the Gainesville, Ga.-based fuel supplier Mansfield Oil.

"Demand is off substantially, by some indications up to 8 percent," he said. "With folks buying less, there is ample supply, which drives down prices."

Demand has fallen, not just for gas itself, but for the crude oil from which it is produced. And that drop has not been limited to the United States, said Ken Stern, a managing director in the New York office of the consulting firm LECG.

"Crude is way off, not just in the U.S., but around the world," he said, citing China in particular. In recent years, the world's most populous nation has tremendously expanded its energy consumption.

But supply and demand are not the only factors at work, said Darin Newsom, senior analyst with Omaha, Neb.-based DTN. Speculation played a part in crude's rise, and is now playing a part in its fall.

"This entire financial market crisis has been played out in commodities as well," he said, "with speculative traders rushing to get out of the markets as quickly as possible ... there are fewer buyers and a lot of sellers wanting to get out of this thing."

As a result, the price of crude oil has fallen from a record $147 a barrel in July to the mid-$80s. The Organization of the Petroleum Exporting Countries decided last month to cut production by 520,000 barrels, but that was not enough to halt the slide.

"While they may now be reversing course there has been plenty of crude oil to go around for months," Mr. Haugh said.

As crude oil prices have fallen, so have those for gasoline -- but not proportionally, said Robert K. Kaufmann, director of the Center for Energy and Environmental Studies at Boston University.

"We've not seen the full effects of the reduction in crude prices follow through," he said. "I think crude prices could decline another $10 a barrel, into the upper $70s or low $80s." If crude oil reaches those prices, gasoline "could be just slightly below or around $3 a gallon," he said.

Mr. Haugh said crude might drop even further between now and spring, to around $70, producing a price for gas around $2.70.

"The wild card as always is geopolitics, not fundamentals," he said, noting that Saudi Arabia and Russia are "making noise now" about cutting back production further.

With the summer driving season behind us, the next seasonal increase in demand will be Thanksgiving, one of the times when Americans travel most.

"I don't think it's unreasonable to think that it be under $3 and will stay there for some time," said Mr. Stern.

Mr. Haugh had a similar prediction. "It's a good bet we'll be below $3."

Mr. Newsom and Mr. Kaufmann offered less optimistic estimates of $3 to $3.10, still a significant drop from today's prices.

Oil closed down yesterday after touching its lowest level this year. Light, sweet crude for November delivery fell $1.11 to $88.95 on the New York Mercantile Exchange.