Tight supplies of gasoline and diesel fuel are pushing up prices at the pump and causing temporary outages at some retail stations in Iowa. Transport truckers must drive longer distances and spend time waiting at major terminals, such as Des Moines, to get fuel loads for retailers because some outlying terminals are out of fuel, said Dawn Carlson, president of the Petroleum Marketers and Convenience Stores of Iowa.

Outages have occurred at some stores across the state, although the shortage has gone unnoticed to motorists for the most part because transporters have done “one heck of a job” in making deliveries, Carlson told the Des Moines Register. Sometimes fuel supplies are replenished within several hours, but some outages last longer, Carlson said.

A Casey’s General Store in Cedar Rapids was without premium and 10% ethanol blend for a couple of days earlier this week, although the store still had regular unleaded, said Danielle McGuin, an assistant manager.

Longer transport distances add several cents to the price of a gallon of gasoline in Iowa, Carlson said. Prices had already been pushed up by higher crude oil prices. The average Iowa price for unleaded regular was $3.08 a gallon on Friday, about a penny above the national average, according to the AAA Daily Fuel Gauge Report. The price at many Des Moines-area stations, however, was $3.12, with 10 percent ethanol at about $2.99.

Gov. Chet Culver is considering an order to allow truck drivers to work longer hours to make deliveries because of the additional time they have to spend waiting in line for fuel, spokesman Brad Anderson told the newspaper. A similar order was issued in July when the supply market tightened.

The problem isn’t confined to Iowa. North Dakota Gov. John Hoeven last week extended a driving-hours waiver for commercial truck drivers providing gas stations with fuel. He cited a potential shortage of diesel fuel.