Gas prices in the United States fell below $4 a gallon on Thursday, retreating to their lowest level since March, a sign of relief for Americans struggling with historically high inflation and a political boost for President Biden, who has been under pressure to do more to bring down prices.

The national average cost of a gallon of regular gasoline now stands at $3.99, according to AAA. That’s still higher than it was a year ago but well below a peak of nearly $5.02 in mid-June. The average price has fallen for 58 consecutive days.

Energy costs feed into broad measures of inflation, so the drop is also good news for policymakers who have struggled to contain rising prices. It is a welcome development for Mr. Biden, who has spent recent weeks trumpeting the drop in gasoline prices, even as he pledges to do more to bring costs down. Mr. Biden has criticized oil companies for their record profits, and this year he released some of the nation’s stockpile of oil in an effort to reduce price pressures.

cost of gasoline at the pump is determined by global oil prices, which have tumbled to their lowest point since the war in Ukraine began in February, a drop that reflects in part the growing concern of a worldwide recession that will hit demand for crude.

said in a statement, citing it as one example of recent “encouraging economic developments.”

For consumers, falling gas prices offer a respite from a shaky economy, rapid inflation and other worries. “We have new rising diseases and inflation, and people expect a recession,” said Zindy Contreras, a student and part-time waitress in Los Angeles. “If I just had to not worry about my gas tank taking up $70, that’d be a huge relief, for once.”

Ms. Contreras has been filling up her 2008 Mazda 3 only halfway as a result of the higher prices, costing her $25 to $30 each visit to the pump, and she had found opportunities to car-pool with friends. These days, Ms. Contreras usually gets gas twice a week, driving 15 miles to and from work each week and an additional 10 to 50 miles a week, depending on her plans.

The national average price masks wide regional variations. Prices vary according to the health of local economies, proximity to refineries and state taxes, said Devin Gladden, a spokesman with AAA.

weaker demand because of high costs, a sharp decline in global oil prices in recent months and the suspension of taxes on gasoline in a handful of states.

Nearly two-thirds of people in a recent AAA survey said they had altered their driving habits because of high prices, mostly by taking fewer trips and combining errands. On Thursday, the Organization of the Petroleum Exporting Countries revised down its forecast for global oil demand this year.

Regardless of the causes, the lower prices are a welcome change for drivers for whom the added expense — often $10 to $15 extra for a tank of gas — had become yet another hurdle as they sought to get their lives back to normal as the coronavirus pandemic eased.

“The affordability squeeze is becoming very real when you see these high prices at the gas pump,” said Beth Ann Bovino, the U.S. chief economist at S&P Global. “So, in that sense, it’s a positive sign certainly for those folks that are struggling.”

That cushion — cash not spent on gasoline that can go elsewhere — also extends to businesses, particularly as the price of diesel fuel drops. Diesel, which is used to fuel, for instance, farm equipment, construction machinery and long-haul trucks, has also fallen from a June record, though at a slower pace than gasoline prices.

The drop in the price of gas is also good news for the economy, as businesses face less pressure to pass energy costs on to their customers — a move that would add to the country’s inflation problem.