The national average price for on highway diesel reached 5.348 dollars per gallon for the week ending August 3, according to Department of Energy data reported by Transport Topics, up 3.5 cents from the prior week. The increase extends a reversal that began in early July, when diesel had fallen for ten straight weeks to 4.58 dollars per gallon before climbing back above 5.30 by month's end.
The West Coast and California carried the highest regional averages at 6.13 and 6.72 dollars per gallon respectively, while the Gulf Coast remained the cheapest region at 5.14. The swing followed a stretch of unusual volatility. Diesel dropped more than a dollar per gallon between May and early July before reversing sharply, driven in part by tightened global supply following a Russian ban on diesel exports and reduced refinery throughput tied to shipping disruptions near the Strait of Hormuz.
The Energy Information Administration had projected a full year 2026 average of 4.87 dollars per gallon in June, then revised that forecast down to 4.61 dollars in early July. Diesel has since traded well above both figures, leaving fuel surcharge calculations built on older forecasts lagging current pump prices.
For carriers, the swing matters beyond the sticker price. The American Transportation Research Institute found average operating costs already hit a record 2.336 dollars per mile in 2025, and diesel is typically the second largest line item after labor. Fleets that price fuel surcharges off monthly averages rather than current weekly data risk undercharging for the fuel they are actually burning.
Source: Transport Topics - https://www.ttnews.com/2026-doe-regional-diesel-fuel-prices