The average U.S. price for diesel climbed to a record $6.05 a gallon Friday, adding pressure to the freight networks that move food, packages and other everyday goods through local communities. The price rose from $5.85 a gallon a week earlier and $3.70 at the same time last year, according to AAA. Regular gasoline also reached a national average of $4.29 a gallon Friday, up from $2.98 before the war between the United States and Iran began in late February. The fuel spike is being driven largely by higher crude oil prices and disruptions to energy shipments in the Middle East. Brent crude, the international benchmark, traded above $105 a barrel Friday, compared with roughly $70 before the conflict. Tanker traffic through the Strait of Hormuz, a major oil-shipping route, has faced severe constraints as fighting has intensified. For households, the effects may appear gradually. Diesel powers much of the trucking, rail and delivery infrastructure that supplies supermarkets and businesses. It is also used in farm equipment, fishing boats, refrigerated transport, buses, trains and emergency generators. Food could be among the first areas where residents notice the added expense. The Independent Grocers Alliance estimates that fuel accounts for about 15% to 30% of the total cost of food. Perishable goods such as meat, seafood and produce require frequent transportation and refrigeration, leaving them particularly exposed to rising fuel costs. David Ortega, a professor of food economics and policy at Michigan State University, said grocery prices may not immediately reflect higher fuel bills because freight contracts and retailer margins can temporarily absorb the increase. Over time, he said, renewed contracts and fuel surcharges are likely to push more of the cost to shoppers. U.S. grocery prices were 2.7% higher in July than a year earlier, while seafood prices rose 7% and fresh fruit increased 4.9%, according to the figures cited by Ortega. Transportation costs are only one factor in those changes; weather, disease outbreaks and shifts in consumer demand can also affect prices. Businesses that ship goods have already begun adding fuel-related charges. Amazon introduced a temporary 3.5% fuel and logistics surcharge in April for some third-party sellers. UPS, FedEx and the U.S. Postal Service also added fees to some shipments earlier in the conflict as fuel expenses increased. The longer diesel remains expensive, the greater the risk that surcharges and transportation costs will spread to products ranging from clothing and furniture to cosmetics. Small businesses and low-income households may have less room to absorb those increases, while communities dependent on long-distance deliveries could face especially steep costs. Diesel prices have been higher in inflation-adjusted terms. Government data show that the price before the 2008 financial crisis was about $4.74 a gallon, equivalent to roughly $7.20 in 2026 dollars. The 2022 record of nearly $5.82 a gallon would equal about $6.56 today. Still, the current increase is significant because diesel is difficult to replace in much of the commercial transportation system. Drivers can sometimes reduce gasoline use, but freight companies, farms and delivery networks have fewer immediate alternatives. S&P Global Energy does not expect Middle Eastern crude production to return to prewar levels by the end of 2027. Jim Burkhard, the firm’s vice president and global head of crude oil research, said the market is adapting to lasting security and logistical problems rather than returning to normal conditions. President Donald Trump has said oil prices may not fall until after the November midterm elections, while continuing to downplay the war’s economic effects. For consumers and local businesses, the immediate concern is more practical: whether an extended fuel shock will keep raising the cost of getting food and other necessities to store shelves and front doors.