The U.S. Energy Information Administration reports a national on-highway diesel average of $6.285 per gallon for September 14—up 31.8 cents in one week and $2.546 from a year earlier.
The national average rose to $6.285
The U.S. Energy Information Administration's September 15 release put the national average retail price for on-highway diesel at $6.285 per gallon for Monday, September 14, 2026. That was 31.8 cents higher than the September 7 average of $5.967. EIA's table says the latest national price was $2.546 per gallon above the comparable year-earlier level.
The weekly series includes taxes
EIA states that the published diesel prices include all taxes. Its methodology describes the figure as a volume-weighted average estimate of the cash self-serve pump price for ultra-low sulfur on-highway diesel at sampled retail outlets. It is not a guaranteed price at a particular truck stop, a wholesale rack price or a carrier's net cost after discounts and rebates.
Every published region increased
The East Coast average reached $6.158, up 41.4 cents for the week; the Midwest reached $6.250, up 30.4 cents; the Gulf Coast reached $6.027, up 27.3 cents; the Rocky Mountain region reached $6.066, up 26.1 cents; and the West Coast reached $7.250, up 26.3 cents. The Gulf Coast remained the lowest of the five broad regional averages in the September 14 table.
California crossed $8 per gallon
EIA reported a California average of $8.039 per gallon, 27.5 cents above the previous week and $3.068 above the year-earlier comparison. The West Coast excluding California averaged $6.566. These are regional and state estimates; actual cardlock, retail and truck-lane prices vary by location, purchasing program and transaction.
The Lower Atlantic posted the largest listed weekly increase
Within the East Coast subdivisions, New England averaged $6.202, the Central Atlantic $6.312 and the Lower Atlantic $6.096. The Lower Atlantic's 49.1-cent weekly increase was the largest among the regions and subregions displayed in EIA's national table. A one-week move does not by itself establish the direction of future prices.
How EIA produces the estimate
EIA says it surveys a sample of truck stops and service stations that sell retail on-highway diesel. Prices represent the cash self-serve offer at 8:00 a.m. local time on Monday, and the agency uses annual sales volumes to calculate weighted national, regional and California estimates. The current sample methodology began in June 2022, so users should follow EIA's comparability note when analyzing older series.
Fuel surcharges are not set by EIA
EIA explicitly says it does not calculate, assess or regulate diesel fuel surcharges. Shippers and transportation companies privately negotiate those arrangements and may use different formulas. Many organizations reference EIA's weekly data, but the published average does not automatically change a contract. The agreement's chosen index, base price, calculation date, mileage basis and rounding rules control.
What carriers should review
Confirm which EIA geography and release date each customer or broker contract uses, then calculate the surcharge exactly as written. Update dispatch and pricing assumptions, verify fuel-card discounts, examine out-of-route purchases and compare lane revenue with current operating cost. Preserve the official release used for an invoice so both sides can reproduce the calculation later.
What owner-operators should calculate
Convert the weekly fuel move into cost per mile using the truck's actual miles per gallon, then compare paid miles, deadhead, idle use and reimbursed surcharge. A 31.8-cent increase adds about 5.3 cents per mile for a truck averaging 6 mpg before discounts, taxes already embedded in the price, or surcharge recovery are considered. Use the truck's real records rather than that illustration for business decisions.
Drivers can reduce waste without compromising safety
Trip planning can reduce out-of-route fueling, unnecessary idling and missed low-cost stops. Maintain legal speed, tire pressure and preventive maintenance while choosing fuel stops that fit hours-of-service, parking and route restrictions. Do not bypass inspections, run below a safe fuel reserve or park illegally to chase a lower posted price.
What the release does not mean
The September 15 publication is a statistical price update, not a new FMCSA rule, emergency waiver or federal fuel-surcharge mandate. It does not predict next week's number and does not establish what a carrier must pay a driver. Contracts, compensation policies and local pump transactions remain separate from EIA's national and regional averages.
Next update is scheduled for September 22
EIA lists September 22, 2026 as the next release date. Fleets using the series should retain the September 15 table and check the next publication rather than treating a copied social-media figure as current. CDL Truck Pro will continue to distinguish the observation date—September 14—from the release date—September 15—when referencing this weekly series.
Continue with CDL Truck Pro
Official sources
EIA Gasoline and Diesel Fuel Update, released September 15, 2026EIA methodology for weekly on-highway diesel estimatesEIA FAQ: Diesel fuel surchargesCDL Truck Pro provides educational information. Confirm licensing, safety, tax, and regulatory requirements through current official sources and qualified professionals.