
Diesel Spiked 40 Cents Last Quarter. Here's How Optimized Fleets Felt Almost None of It.
Direct Answer
Contracted fuel pricing only protects fleets from part of diesel volatility. Within a single network, contracted prices vary $0.18–$0.31 per gallon between stations on the same day. Without route optimization, drivers fuel at the first contracted station they see, which is rarely the cheapest one on the route, so the fleet absorbs most of every quarterly diesel swing anyway.
Key Statistics
- On-highway diesel typically swings $0.30–$0.60 per gallon over a single quarter (EIA data).
- Same-day contracted-price spread inside one fuel network commonly runs $0.18–$0.31/gal across stations.
- Which contracted station a truck fills at is decided on every route, so that same-day spread is either captured on the run or paid on it.
Your fuel contracts protect you from part of the market. Route optimization protects you from the rest. Most fleets are only using half the hedge.
Diesel hit a 14-month high in January. By March it had dropped $0.38.
If your fuel spend moves in lockstep with those swings, you have a volatility problem, even if you have contracted pricing. And in a tight freight market where fuel is 25-40% of operating cost, a $0.38/gallon swing on 200,000 gallons a year is $76,000 gone in a quarter, returned the next, then gone again.
The fleets that have insulated themselves from most of this aren't buying fuel futures. They're not hedging with financial instruments. They're doing something much simpler: they're making sure every dollar of fuel they buy comes from the cheapest contracted station on the route, every time.
Why Contracted Pricing Doesn't Fully Protect You
Most fleet operators understand that contracted pricing gives them a discount off retail at network stations. What's less understood is that contracted pricing doesn't eliminate price variation. It reduces it, but meaningful variation remains.
Within a single fuel network, contracted prices at different stations along a route can vary by $0.18-$0.31 per gallon on the same day. That's not a market swing. That's a structural spread that exists because of how networks set regional pricing, state tax differentials, and local demand patterns.
When a driver fuels at the first contracted station they see rather than the cheapest contracted station on the route, they're buying at the high end of your own contracted spread. You negotiated that discount once and then spend part of it back at the pump, fill by fill, for the life of the contract.
The Spread Is Inside Your Own Contract
This is the part that surprises people. The spread is not between your contract and retail. You already won that one at the negotiating table. The spread is between the cheapest station your contract covers on a given corridor and the one your driver happened to reach first.
Nobody has to be doing anything wrong for it to cost you. The driver is following the route. The contract is being honored. The money leaves anyway, one fill at a time.
The Two Sources of Fuel Cost Volatility
Fleet fuel volatility has two distinct sources that require two different responses:
- Market volatility: the broad movement of diesel prices driven by crude oil, refining margins, geopolitics, and seasonal demand. This is what everyone watches on the EIA weekly report. Contracted pricing addresses this by locking in a discount structure that scales with the market rather than exposing you to full retail.
- Intra-contract volatility: the spread between cheapest and most expensive stations within your existing contract on any given route. Almost nobody manages this systematically, and it's where most of the recoverable savings live.
Most fleet fuel strategies address market volatility reasonably well. Almost none address intra-contract volatility at all.
How Route Optimization Functions as a Hedge
When you optimize fuel stops against your actual contracted prices (not averages, not retail, but your specific rates at your specific stations) you are systematically buying at the low end of your contract spread on every route, every time.
This does two things simultaneously:
- It captures the intra-contract spread (the station-to-station variation inside your own network) as a realized saving, not a theoretical one.
- It buffers market swings. When diesel prices rise, the cheapest contracted stations rise less than the most expensive ones (the spread widens). Optimization routes drivers to the lowest-cost stations, partially insulating total fuel spend from the full magnitude of the market move.
The order matters. A contract alone moves your whole cost curve down and leaves you riding the market from wherever that curve happens to sit. A contract plus optimization moves the curve down and then keeps you at the bottom of it, which is the only part of a price spike you have any control over once it starts.
The Compounding Effect
Diesel volatility isn't a one-time event. EIA data from 2022-2025 shows an average of 3-4 significant price swing events per year, each moving $0.20-$0.60 per gallon. Each swing is a moment where the gap between optimized and unoptimized fleets widens.
The cumulative effect over a year is two different operating realities. One fleet meets every swing at whatever price its drivers happen to land on inside the contract. The other meets every swing at the bottom of that same contract, on every route, without anyone in the office doing anything about it.
What This Means for Your Fuel Budget
Fuel budgeting in trucking is notoriously difficult because the market is inherently unpredictable. Most fleet managers pad their fuel budget to account for volatility, and then watch that buffer disappear in Q1 every time there's a supply disruption.
Route optimization doesn't eliminate the need for a fuel budget buffer. But it reduces the size of the buffer you need, because a larger portion of your total fuel spend is now insulated from the worst of the market swings. Fleets using OptiMile Pro routinely report tighter fuel budget variance. They stopped buying at the expensive end of their own contract, and the numbers show it.
The simplest fuel hedge you're not using
You already negotiated the contracts. OptiMile Pro makes sure you're buying at the low end of every one of them, on every route, every day. Start your free trial and see your contracted price spread on your actual routes. Most fleets are looking at their own spread for the first time inside the first week.
Start Free TrialFrequently Asked Questions
Sources
- Weekly On-Highway Diesel Prices, U.S. Energy Information Administration
- An Analysis of the Operational Costs of Trucking, American Transportation Research Institute (ATRI)
- FleetOwner: Fuel & Lubricants, FleetOwner
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