It will cost a little less to drive this holiday weekend as gasoline prices have dropped 20 cents a gallon in a month.

The average cost for a gallon of regular in New Jersey is now $3.23, the lowest for a Labor Day weekend in four years. Gas is going for about $3.44 a gallon in the Philly area and $3.34 in Delaware.

Pump prices have followed declining crude oil prices, said Tom Kloza, chief oil analyst at GasBuddy.com.

"It's backed off because Chinese demand is a little bit more sluggish, but mostly because U.S. production of crude is about 3.1 million barrels a day higher than it was during the first Arab Spring and that's on course to break records," he said. "We're going to break the production record that was established in 1972 when Nixon was President."

A mid-September switch from summer-blend gasoline to easier-to-produce blends and the usual falloff in travel after Labor Day will help keep prices low, Kloza said.

"Demand drops by about 400,000 barrels a day or about 17 million gallons a day after Labor Day, so everything is in our favor for the next few months. I think they'll go higher from wherever we bottom out -- let's say between Election Day and Groundhog Day," he said. "They'll go up again next spring."

The lack of production-disrupting storms this summer also has helped keep gas prices from rising.