Diesel Hit $6.29 a Gallon — Up 68% in a Year — Just as Spot Rates Had Their Worst August on Record

The national average price for on-highway diesel hit $6.285 a gallon in the week of Sept. 14, 2026, according to the Energy Information Administration. A year earlier it was $3.739. That is an increase of $2.55 a gallon, or 68%, and it happened mostly in the last ten weeks.

In the same stretch, the spot market went the other direction. DAT reported that the national average van spot linehaul rate fell 20 cents in August to $2.19 a mile — an 8.4% drop, the steepest August decline in the history of the data, beating the previous record of 6.7% set in 2018.

Costs up sharply, revenue down sharply. That is the shape of the market right now.

This is a news summary, not financial advice.

How fast diesel moved

EIA weekly national average, on-highway diesel:

From the January low of $3.459 to Sept. 14 is a rise of $2.83 a gallon. A truck running 120,000 miles a year at 6.5 mpg burns roughly 18,500 gallons — so that swing is on the order of $52,000 a year per truck in fuel, before any surcharge recovery.

Regionally on Sept. 14, the spread was narrower than the headline suggests: Central Atlantic $6.312, Midwest $6.250, New England $6.202, East Coast $6.158, Lower Atlantic $6.096, Rocky Mountain $6.066, Gulf Coast $6.027.

Analysts attribute the run-up to a distillate supply problem rather than a crude problem: refinery outages, sharply reduced Russian diesel exports, sanctions and conflict-related disruption to global flows, and jet fuel competing with diesel for the same middle-distillate barrels. Notably, diesel has been setting records even during stretches when crude eased — which is the signature of a refining and distillate bottleneck, not a general oil rally.

What happened to rates

DAT's August numbers, spot linehaul (excluding fuel surcharge):

Contract rates held up better: dry van $2.41, reefer $2.65. That puts the spot-to-contract gap at 22 cents for van and just 4 cents for reefer.

Volumes fell too — DAT's Truckload Volume Index was down 5% for van, 2% for reefer and 3% for flatbed month over month.

Dean Croke, DAT's principal industry analyst, attributed much of it to timing rather than collapse: "Last month's decreases in rates and volumes in large part reflect normal seasonality and freight that shippers pulled forward earlier in the summer."

The part that actually hurts: the surcharge gap

Fuel surcharges did rise in August — van to 70 cents a mile (up 8 cents), reefer to 77 cents (up 10 cents), flatbed to 84 cents (up 10 cents). So the all-in rate fell less than the linehaul number implies.

But surcharges have three structural problems, and all three are worse when diesel is moving this fast:

1. They lag. Most surcharge schedules key off a weekly or even monthly EIA average. When diesel rises 32 cents in a single week, as it did between Sept. 7 and Sept. 14, you buy fuel at today's price and get reimbursed at last week's.
2. They pay on loaded miles. Deadhead and out-of-route miles burn fuel that no surcharge covers. At $3.50 diesel that gap was an annoyance. At $6.29 it is a line item.
3. The peg may be stale. Many schedules were built around a base price of $1.20 to $1.50 a gallon with a set cents-per-mile step. Schedules that have not been revisited in years under-recover badly at these levels.

If you have not re-run your surcharge math against actual fuel receipts this quarter, that is the highest-value hour you can spend this week.

The capacity picture underneath

There is a reason rates have not fallen further. Capacity has been leaving.

ATRI found carriers cut truck counts 2.4% in 2025 — the largest reduction since the freight recession began in 2022 — while leaving about 10% of trucks unseated and cutting non-driver staffing 7.8%. FMCSA's quarterly data showed carrier revocations in the first quarter of 2026 at their lowest level of any quarter since Q4 2021, with grants and reinstatements exceeding revocations for the first time since mid-2025.

FTR's Avery Vise has cautioned that diesel shocks may not show up in carrier-population data for months, if at all, and that employment in the sector has remained historically depressed.

Translation: the market is tight on capacity and soft on demand at the same time. Fuel is now the variable most likely to force more capacity out — and the carriers most exposed are the ones with the weakest surcharge terms and the thinnest cash reserves.

What to do this month

1. Recalculate your surcharge against receipts, not against the schedule. Find the actual gap per mile.
2. Renegotiate the peg, not just the rate. A base price set years ago is the silent leak.
3. Get surcharge language into spot quotes, not just contracts.
4. Attack empty miles. Every deadhead mile is now unreimbursed at record cost.
5. Watch idle time and speed. At $6.29 a gallon, a tenth of a mile per gallon is worth real money — roughly $1,800 a year on 120,000 miles.
6. Reprice your lanes. A lane that penciled at $4.50 diesel may not at $6.29, especially a long deadhead back.
7. Check your cash position before your rate sheet. Fuel is a weekly cash outflow; freight pays in 30 days or more. Carriers fail on timing, not margin.

Quick answers

What is the current national average diesel price? $6.285 a gallon for the week of Sept. 14, 2026, per EIA — up $2.55 from a year earlier.

Are spot rates collapsing? August was the steepest August drop on record for linehaul, but DAT attributes much of it to seasonality and freight pulled forward earlier in the summer. Contract rates held up better.

Why is diesel rising when crude isn't? Diesel comes from middle distillates, and the constraint is refining and distillate supply — outages, reduced exports from sanctioned sources, and jet fuel competing for the same barrels.

Will fuel surcharges cover this? Partly. They lag the market and generally pay only on loaded miles, so fast increases and high empty-mile percentages leave real money uncovered.

Sources

• EIA: Gasoline and Diesel Fuel Update
• USDA Agricultural Transport Open Data: Weekly On-Highway Diesel Fuel Prices
• DAT: Spot van rate falls 20 cents in steepest August pullback on record
• Trucking Dive: Carrier population shifts back toward growth, quarterly FMCSA data shows
• ATRI: New Report Details Accelerating Costs and Low Profitability Despite Cuts