Metro Atlanta gas prices, which surpassed the $4 mark in July, dropped below $3.90 this weekend.

Saturday morning's metro area average was $3.86 for regular unleaded, according to AAA's gas station survey — down 24 cents a gallon from the July 17 peak of $4.10.

The Web site atlantagasprices.com, which compiles averages from driver reports, showed an even lower average Saturday of $3.83 in the Atlanta metro area, compared to $3.93 a week ago.

The metro Atlanta decreases are in line with national trends. According to the Lundberg Survey of 7,000 gas stations nationwide, prices are at their lowest level since mid-May and are an average of 11.7 cents per gallon lower than two weeks ago.

The steep decline may not be permanent — government forecasts still have prices hovering around $4 into 2009 — but it has at least eased the sticker shock at the pump caused by constant increases in the spring and early summer.

The drop tracks the slide in crude oil prices, which fell more than $20 a barrel in the latter half of July.

Oil prices kept falling Friday on expectations that slowing economic growth in developed countries will cut demand for crude products, such as gasoline and heating oil.