Nikki Apitz can’t go anywhere for less than $100 these days.

“It’s insane,” the Rockford resident said Thursday as she filled up her tank Thursday at a Road Ranger in Dixon, where gas cost $4.47 per gallon. Across the street, it costs around 30 cents more per gallon.

Prices have been rising since the Iran war began on Feb. 28.

They’re up well over $1 nationwide, and in March, they jumped up by almost 21% compared with the previous month, the Associated Press reported. Just this past week, prices rose an average of 56 cents per gallon in Illinois, said Patrick De Haan, the head of petroleum analysis for GasBuddy.

The sharp rise in prices has been attributed to the war’s disruption to the Strait of Hormuz, a narrow passage of water between the Persian Gulf and the Gulf of Oman, typically used to transport around a fifth of the world’s traded oil every day. Iran forced the closure of the Strait through mines after the war began, and U.S. President Donald Trump reciprocated by imposing a blockade of Iranian ports, the AP reported.

If global oil supplies continue to be constrained by the disruption in the Strait, the national average for gas could push beyond the $4-per-gallon mark, and diesel could approach $6 per gallon, potentially setting new record highs, De Haan said in a news release.

However, the biggest driver behind the price surge in the Midwest this week was a power issue at the BP Whiting refinery in Indiana, one of the largest oil refineries in the U.S., located about 17 miles from downtown Chicago, De Haan said.

The Midwest is relatively isolated from other fuel supply centers, so when issues occur at a major one, prices react fast, although operations at BP Whiting have stabilized. Those increases flow down to customers quickly because many stations refill tanks at higher costs, De Haan said.

Across Illinois, gasoline cost an average of $4.73 a gallon on Thursday. It rose to an average of $4.90 on Friday, according to GasBuddy.

“It’s Trump’s war, Trump’s gas prices, Trump’s tariffs,” Dixon resident Woody Wasson told Shaw Local while filling his tank at that same Road Ranger on Thursday.

“Everything he [Trump] says is destroying the country,” Wasson said. “We’re the victims of billionaires.” Gas “had been under $3.”

The hardest part, Apitz said, is “we pay all this gas,” but groceries are costing “five times the amount, too.”

A key inflation measure monitored by the Fed rose 0.7% month-over-month in March. Prices rose 3.5% compared to last year, the biggest increase in almost three years, the AP reported.

“Gasoline really cuts into consumers’ budgets quite a bit. ... That’s going to put a downward drag on the economy, and then that kind of starts a cycle,” Jeremy Groves, an associate professor of economics at Northern Illinois University, told Shaw Local in a prior interview.

“I think it’s probably also going to impact the U.S. a little bit more [than the global economy],” Groves said, “because we are more car- and auto-oriented.”

In Kankakee, gas cost $4.49 at the Casey’s at 1075 W. Jeffery St. on Thursday, and rose to $4.79 on Friday, according to GasBuddy.

Prices also went up on Friday in Joliet. It cost $4.53 at the Citgo at 555 E. Cass St. on Thursday and $4.65 on Friday, according to GasBuddy.

In McHenry and Aurora, prices are higher but more stable. It cost $4.99 on Thursday and Friday at the Mobil at 4416 W. Elm St. in McHenry and at the Speedway at 948 N. Farnsworth Ave. in Aurora, according to GasBuddy.

On Thursday, prices ranged from $4.69 to $5.79 at stations in Chicago. Prices at some stations jumped to $5.99 on Friday, according to GasBuddy.

GasBuddy data showed that prices for diesel also rose within the last two days.

In Dixon, diesel cost $5.19 at the Murphy USA at 1620 S. Galena Ave. and cost $5.69 on Friday. A similar jump occurred at the Jeffery Street Casey’s in Kankakee. Diesel cost $5.49 on Thursday and $5.69 on Friday, according to GasBuddy.

On Thursday and Friday, diesel cost $5.26 at the Casey’s at 1901 N. Richmond Road in McHenry; $5.17 at the Cass Street Citgo in Joliet; and $6.19 at the Farnsworth Avenue Speedway in Aurora, according to GasBuddy.

On Thursday, prices ranged from $4.99 to $6.15 for diesel at stations in Chicago. The high point of that range rose to $6.69 on Friday, according to GasBuddy.

These price spikes could go down once refinery operations fully normalize, but the broader trend of high prices remains an issue due to the war and political climate, De Haan said.