Diesel Retreats, but $6.38 Benchmark Keeps Fleets Under Pressure

Diesel moves lower, but the relief is limited

The latest national diesel reading gave trucking a modest break, not a reset.

The U.S. Energy Information Administration's weekly survey, released September 29 and measuring prices as of September 28, put the national average price for on-highway diesel at **$6.382 per gallon**, including taxes. That was down **14.7 cents** from the prior week's $6.529 average.

For carriers, owner-operators and drivers who buy fuel directly, the decline is welcome. But the bigger figure remains the year-over-year comparison: diesel was still **$2.628 per gallon higher than the same week in 2025**. In other words, the weekly price eased, but the operating-cost pressure remains extraordinarily high.

That makes the September 29 EIA update an important signal for trucking. Fuel buyers should not confuse one lower weekly benchmark with a return to normal fuel conditions.

What the latest EIA data shows

The national average fell from the September 21 reading, but diesel remains expensive across every major EIA region.

Here is the September 28 benchmark by region:

• **East Coast:** $6.137 per gallon
• **Midwest:** $6.526 per gallon
• **Gulf Coast:** $5.955 per gallon
• **Rocky Mountain:** $6.407 per gallon
• **West Coast:** $7.357 per gallon
• **California:** $8.181 per gallon

The Gulf Coast posted the lowest regional average in the EIA survey, while California remained the highest-cost market by a wide margin. The $2.226-per-gallon difference between those two readings illustrates why fuel strategy, routing and customer pricing can look very different from one operation to another.

The Midwest matters especially for many truckload and refrigerated carriers because it recorded a $6.526 average despite a 15.4-cent week-to-week decline. The West Coast's $7.357 average fell 9.9 cents, while California's $8.181 average declined 6.5 cents. Those reductions are real, but they leave fuel costs at levels that can quickly erase margin on poorly priced freight.

Why a lower weekly price does not solve the cost problem

A 14.7-cent decline sounds meaningful at the pump. On a 150-gallon fill, it is about **$22 less** than the prior week's EIA benchmark. That matters, particularly for small fleets and independent operators managing cash flow day to day.

But the year-over-year gap tells the harder story. At $6.382 per gallon, a 150-gallon fill costs roughly **$957** before any fuel-discount adjustments. At the comparable benchmark a year earlier, that same quantity would have cost about **$563**. The difference is approximately **$394 per fill-up**.

Actual gallons purchased, negotiated fuel discounts, idle time, speed, route terrain and equipment all change the final result. Still, the calculation shows why a weekly dip alone does not restore margins. The current benchmark is nearly 70% above its year-earlier level.

For a carrier that has fuel-surcharge language tied to the EIA index, the lower benchmark may eventually reduce surcharge payments under some customer agreements. But that does not necessarily mean a company's total fuel expense is suddenly manageable. Surcharge schedules, trigger points, mileage assumptions and timing differ by contract. Some agreements also lag the weekly EIA movement.

Tight distillate supplies remain a concern

The latest pump-price move comes against a broader supply picture that still looks tight.

In its September Short-Term Energy Outlook, EIA forecast that U.S. distillate fuel oil inventories would fall below 100 million barrels in September and remain below the 2021-2025 five-year low through the end of 2026 and much of 2027. Diesel is a major distillate fuel product.

That forecast does not mean diesel prices must rise every week. Retail fuel prices can move with crude oil, refinery operations, wholesale diesel markets, transportation costs and local supply conditions. It does mean the market has less room for disruption than it would with more comfortable inventories.

For trucking, this is the practical takeaway: the recent decline may be a short-term improvement inside a still-costly fuel environment. It is not evidence that fleets should stop monitoring fuel exposure or assume the next several months will be stable.

Independent trucking reporting published September 29 also described a market where stronger freight rates have been offset in part by elevated diesel costs. That tension is central to carrier profitability: rate gains help only when they exceed the added cost of operating the truck.

Who is affected most

Owner-operators and small fleets

Fuel is one of the largest variable costs for an owner-operator or small carrier. A business with limited buying power, limited working capital or freight booked without a workable fuel component is particularly exposed.

Practical priorities include:

• Reviewing every load's all-in revenue, not only the linehaul rate.
• Confirming how fuel surcharges are calculated before accepting recurring freight.
• Comparing network fuel-card prices and discount locations against the cash price posted at the pump.
• Avoiding unnecessary deadhead, idling and out-of-route miles where operationally possible.
• Tracking fuel cost per mile by lane, customer and equipment type.

Larger carriers

National and regional fleets may have broader fuel-discount programs, procurement teams and surcharge mechanisms. Even so, they face exposure when customer contracts have delayed or capped surcharge formulas, or when operating networks place equipment in high-cost regions.

Fleet managers may want to review whether current surcharge tables still reflect the EIA index, whether customer contracts activate quickly enough, and whether regional dispatch decisions account for the sharp California-to-Gulf-Coast price spread.

Drivers and recruiters

Higher diesel does not automatically change driver compensation, but it can influence carrier decisions on freight selection, network design, idle-reduction practices and equipment utilization. Drivers evaluating jobs may find it useful to ask how a carrier manages fuel costs without shifting unreasonable pressure onto the driver.

Recruiters and staffing teams should also expect candidates to pay closer attention to the financial health of prospective employers when fuel costs remain elevated. Clear explanations of freight mix, home-time structure, equipment condition, fuel-card access and compensation can be more valuable than vague claims about stability.

What to watch next

The next EIA weekly diesel update is scheduled for October 6. Fleets should watch both the national benchmark and regional changes rather than relying only on a national headline number.

Key items to monitor include:

• Whether the national price continues falling or resumes rising.
• Changes in the Midwest, Gulf Coast and West Coast regional benchmarks.
• Distillate inventory trends in upcoming EIA petroleum reports.
• Wholesale diesel and crude-oil movements, which can flow into retail pricing with a lag.
• Whether freight rates and fuel-surcharge recoveries are keeping pace with operating costs.

The September 29 update is a reminder that a favorable weekly move can still leave trucking in a difficult cost position. Diesel is down from the prior week, but at $6.382 per gallon nationally and far higher in some regions, fuel discipline remains a core operating issue for the industry.