Diesel Just Set a Record. Redo Your Cost Per Mile Before You Book Another Load.

If you set your minimum rate back in July, that number is already wrong. On July 6 the national diesel average was $4.58 a gallon. On September 14 it was $6.285, the highest weekly reading the Energy Information Administration has published since it started tracking in 1994. That is a $1.70 swing in ten weeks, with 32 cents of it landing in the most recent week alone.

Big carriers absorb that through surcharge tables that update on their own. An owner-operator or small fleet absorbs it by sitting down and redoing the math. If you have not done that since summer, this is the week. It takes about twenty minutes and it will change which loads you say yes to.

What actually changed in the last three weeks

Three things moved at once, and they moved against you. Diesel went from $5.60 on August 31 to $5.97 on September 7 to $6.285 on September 14, per EIA. Spot rates kept easing off the July peak: DAT had dry van at about $2.90 a mile all-in in late August, reefer at $3.36, flatbed at $3.55. And contract rates moved back above spot in all three, which says the summer’s spot strength was not the new baseline.

The one thing still working for you is capacity. DAT’s dry van load-to-truck ratio averaged 9.98 in August against 5.81 a year earlier. Shippers are paying more to move less freight. That gives a well-run small carrier real leverage on rate, but only if you know exactly what your floor is. The market will not reject a bad load for you.

One more signal: on September 16, FMCSA issued a 90 day nationwide hours-of-service waiver for drivers hauling gasoline and diesel, the first nationwide waiver since COVID. It does not apply to general freight, but it tells you fuel supply is being treated as a fall-long issue, not a one week spike.

Rebuild your cost per mile in twenty minutes

ATRI’s 2026 Operational Costs of Trucking report put the industry average at a record $2.336 per mile for 2025, with fuel at just $0.48 of that. Fuel was cheap last year relative to now. At this week’s price, a truck averaging 6.5 miles per gallon burns $0.97 per mile in diesel alone. A truck at 6.0 mpg is at $1.05. Fuel just went from a fifth of your cost stack to a third of it.

Here is the fast version. Pull your last full month of fuel receipts and total the gallons. Pull the same month of miles from your ELD or GPS, every mile, not just the loaded ones. Divide to get your real fleet mpg, which is almost always worse than the number you tell people. Multiply by your regional diesel price, not the national average, since regions ran from about $6.16 on the East Coast to well above that out West. That is your fuel cost per mile for the week.

Then add everything that does not care whether the truck moves: truck payment, insurance (up 6.4 percent in the first quarter of 2026 alone per ATRI, the fastest of any line item), permits, plates, ELD and telematics, and your own pay. Divide by a realistic monthly mileage, not a hopeful one. Add tires, maintenance, and tolls per mile from last quarter’s actuals. That is your all-in cost per mile at this week’s fuel. For many dry van operators it now lands between $2.60 and $2.90, uncomfortably close to a $2.90 spot average.

Deadhead just became the most expensive mile you run

At $0.97 a mile in fuel, a 150 mile deadhead to reach a load costs about $145 in diesel before you count the driver’s time or the hours off your clock. In July that same repositioning cost about $105. The load did not get better. Your cost of reaching it did.

So the question is no longer ‘what does it pay per mile’ but ‘what does it pay including the empty miles to get there and the likely empty miles after.’ A $3.20 load with 200 miles of deadhead can net less than a $2.85 load that reloads in the same yard. With load-to-truck ratios where they are, you have room to be picky about lanes. Use it. Say no to the load that strands you.

Watch the lag between the pump and the surcharge

Most fuel surcharge programs key off the EIA weekly average with a one to two week lag, and many use a base price and a fixed mpg assumption negotiated when diesel was far cheaper. When fuel rises 32 cents in a week, the surcharge you collect this week reflects last week’s price, and the gap comes out of your margin. In a flat market that is a rounding error. In this market it is real money on every load.

Two moves. Know which index and which lag each broker or shipper uses, and plan fuel purchases around the week you are actually being paid for. And check the base price and mpg assumption in any contract up for renewal this fall. A surcharge built on 6.5 mpg when your fleet runs at 5.9 leaves you short on every gallon.

The records that let you say no with confidence

None of this works on memory. It works on records: gallons by state for IFTA, total miles including deadhead from GPS, maintenance and tire spend by truck, insurance certificates, and settlement statements showing what each broker actually paid after the surcharge. If those live in a glovebox, a shoebox, and three vendor logins, the twenty minute rebuild becomes a lost weekend, and most people skip it.

That is the job DocuDrive was built for. GPS tracking, ELD compliance, cameras, and asset tracking on one platform means your mileage and hours come from the same source as your compliance file, with published pricing from $8 a month, free setup, and no contract. When diesel moves again, you rerun the numbers before the coffee gets cold.

The takeaway

Diesel at $6.29 does not have to end a profitable quarter. Rebuild your cost per mile with this week’s fuel price, treat deadhead as the expensive mile it now is, check the lag and base price in every surcharge program you are paid under, and keep the records that make all of it a twenty minute job instead of a guess.

To see where your mileage, fuel, and compliance data are split across systems, the free Fleet Technology Assessment at docudriveapp.com takes about ten minutes. The math is easier than you think, and a lot cheaper than finding out in December.