Average diesel prices in the U.S. have topped $5 a gallon for the first time since 2022, as the ongoing conflict in the Middle East and Iran's closure of the Strait of the Hormuz to nearly all non-Iranian ship traffic continues to disrupt global oil supplies and drive up fuel costs.

CNBC reports that average U.S. diesel prices sat at $5.04 per gallon as of March 17, marking a 34% increase from the first day of strikes by the U.S. and Israel against Iran. That surge is already raising concerns across the freight sector, where fuel represents one of the largest operating expenses for trucking fleets and logistics providers. And as Lipow Oil Associates president Andy Lipow pointed out in a March 17 note, when diesel prices go up, trucking and rail companies increase their own fuel surcharges in response, further straining transportation costs.

Iranian attacks against United Arab Emirates energy infrastructure have added to larger concerns around supplies as well. Recent drone strikes hit key facilities located at the UAE's Shah gas field and Fujairah Oil Industry Zone, forcing temporary shutdowns at one of the Gulf’s most vital hubs for storing and exporting crude oil. Attacks on infrastructure like these could further tighten global supplies, and keep fuel prices elevated if the conflict continues to spread across the region’s energy network.

Read More: U.S. Says It's 'Allowing' Iranian Tankers Through Strait of Hormuz

With no clear end in sight to the war, the U.S. government has continued seeking to provide relief for global oil markets in other ways. On March 12, the U.S. Treasury Department granted temporary exemptions from sanctions to a group of Iranian-linked ships carrying Russian oil, allowing oil already loaded onto more than 370 Iranian tankers to be sold at any price, covering an estimated 215 million barrels of Russian oil. Although the U.S. is not a buyer of Iranian oil itself, the hope is that allowing those shipments to reach global markets will increase available supply and help ease the price pressures that have rippled through energy and freight markets since the conflict began.