Filling up hasn't been this cheap in a long time. (AP/Rich Pedroncelli)

Oil is back below $50 per barrel. Which is to say, it’s incredibly cheap. Still.

Crude is falling again — only months after most economists figured it would stabilize around $65 — because of the same factor that drove it down from even greater heights late last year: full-on production from the biggest players, particularly Saudi Arabia and the United States, that’s led to a major global supply glut. Only this time around, there’s more: Markets have been jittery about China and Europe. Iran figures to scale up as sanctions are relaxed. Meantime, the Saudis aren’t merely producing a lot; they’re producing more than ever before, in a desperate drive for market share.

Add it all together and you have a world with way too much oil on its hands. The gap between supply and demand is so big, you’d have to turn off every pump in a medium-sized oil nation, like Venezuela, just to close it.

Since late June, West Texas Intermediate crude oil is down by 17 percent. Oil company stocks have taken another hit. Gasoline prices should eventually nudge down too, helping U.S. consumers, though the drop is unlikely to be drastic, because U.S. gasoline demand has picked up after years of sluggishness.

U.S. drivers set a monthly record in May for miles logged on the road, according to the Federal Highway Transportation. Driving that month — the most recent for which data is available — was up some 3 percent from the previous year.

“So many people are driving because of the prices, and that has prevented a more significant decline at the pumps,” said Michael Green, a AAA spokesman.

The average gasoline price in the U.S. is $2.74, according to AAA, down from $3.60 a year ago but off from the low of around $2.10 in January. Green said that gasoline could again reach that level, but likely not until the peak summer driving season is over.

Oil began its collapse last year when OPEC — in a departure from a decades-old practice — decided not to curb its production to keep global prices steady. That took WTI oil prices from around $75 per barrel to, by mid-January, around $45.

What’s surprising, though, is how U.S. producers — whose oil is nowhere near as cheap to access as the Saudis’ — have responded. Rather than being elbowed out, most companies have found a way to remain viable — by cutting costs, laying off employees, and drilling only in the best areas. Though the U.S. rig count is down by more than half since last year, oil production has increased. In other words, the U.S. out-maneuvered the price crash — and because of that helped it continue.

In the last few months, those frackers have continued to whittle expenses, said Fadel Gheit, a senior oil analyst at Oppenheimer & Co., an investment firm.

“The companies that broke even at $65 six months ago will now break even at $55,” Gheit said.