Diesel Surges Past $4.48 — Strait of Hormuz Closure Hits Fuel Costs

Why did diesel prices jump $1.32 in a year?

National diesel prices hit $4.48 per gallon this week — $1.32 higher than May 2025 and the steepest level since late July 2022, according to AAA. The spike follows crude oil's climb above $100 per barrel, driven by the ongoing closure of the Strait of Hormuz with no timeline for reopening. For a five-truck fleet running 500 miles per day at 6 mpg, the year-over-year increase adds roughly $550 per truck per week in fuel alone.

AAA's current figure of $4.483 sits 4 cents above the Energy Information Administration's estimate, reflecting rapid movement in wholesale markets. The Strait of Hormuz — the narrow waterway between Oman and Iran through which roughly one-fifth of global oil supply flows — has been closed to tanker traffic for an undisclosed period, choking supply and pushing benchmark crude past the $100 threshold for the first time since 2022.

What the $100 crude floor means for settlement statements

Every dollar-per-barrel move in crude translates to roughly 2.4 cents per gallon at the pump after refining and distribution margins. With crude now anchored above $100 and no sign of the Strait reopening, carriers face sustained pressure on fuel surcharges and net settlement. Spot-market fuel surcharges typically lag pump prices by one to two weeks, meaning owner-operators who locked rates before the spike are absorbing the delta out of pocket until the next load.

Contract carriers with indexed fuel surcharge tables fare better — most tables adjust weekly based on Department of Energy averages — but small fleets running a mix of spot and dedicated freight see uneven protection. A 10-truck operation burning 1,500 gallons per week now pays an additional $1,980 per week compared to May 2025, assuming no offsetting rate increase.

Regional variation and where the pain hits hardest

AAA's national average masks regional swings. West Coast markets — already running 30 to 50 cents above the national mean due to refinery capacity and state fuel taxes — are seeing diesel approach $5 per gallon in California and Washington. Midwest and Gulf Coast states, closer to refinery hubs, are tracking closer to the $4.48 average but still up sharply from last year.

Carriers running long-haul lanes out of the West Coast face a compounding problem: higher fuel costs on the outbound leg and softer backhaul rates as shippers resist rate increases in a still-soft freight environment. The Jones Act waiver extended 90 days for oil and fuel shipments offers no direct relief to trucking fleets — the waiver applies to maritime transport of crude and refined products, not over-the-road diesel distribution.

How long the Strait closure sustains $100 crude

The Strait of Hormuz has been fully or partially closed before — most recently during brief military standoffs in 2019 — but never for an extended period without triggering coordinated releases from strategic petroleum reserves. The current closure, with no announced reopening date, keeps crude markets in backwardation: near-term futures contracts trading above longer-dated ones, a signal that traders expect tight supply to persist.

If the Strait remains shut beyond two weeks, refiners will draw harder on inventories and alternative supply routes — pipelines across Saudi Arabia and the UAE, longer tanker routes around Africa — all of which carry higher costs that flow through to the pump. Small fleets with thin cash reserves face a liquidity crunch: higher weekly fuel bills before fuel surcharge payments catch up, compressing working capital at a time when many carriers are still rebuilding cash after two years of soft rates.

The four-year high and what it signals

The last time diesel averaged above $4.48 was late July 2022, when post-pandemic demand collided with refinery outages and the early months of the war in Ukraine. That spike proved short-lived — diesel fell below $4 by October 2022 as freight demand softened and refinery runs normalized. This time, the supply shock is geopolitical and external to trucking fundamentals, meaning the price floor is less tied to freight volumes and more to how quickly the Strait reopens.

For owner-operators, the 2022 comparison offers limited comfort. Spot rates in mid-2022 were still elevated — dry van averaging $2.50 per mile all-in, enough to absorb fuel swings. Today's spot rates sit closer to $1.85 per mile in many lanes, leaving less margin to weather a sustained fuel spike. Contract rates have held steadier, but most contracts written in Q4 2025 and Q1 2026 assumed diesel in the $3.20 to $3.50 range, not $4.48.

What a 5-truck fleet pays now versus last May

A five-truck fleet running 2,500 miles per week per truck at 6 mpg burns roughly 2,083 gallons per week. At $4.48 per gallon, weekly fuel cost is $9,332. Last May, at $3.16 per gallon, the same operation paid $6,582 per week — a $2,750 weekly increase, or $11,000 per month. Fuel surcharges indexed to the national average will eventually cover most of that delta for contract freight, but spot loads booked before the spike leave the carrier holding the bag until the next load cycles in.

Smaller fleets with less negotiating leverage often run fuel surcharge tables that cap at lower diesel prices or adjust monthly rather than weekly, creating a mismatch when prices move fast. A carrier locked into a monthly-adjusted table set in early April — when diesel was still below $3.50 — won't see relief until June 1, meaning four weeks of out-of-pocket fuel cost.

The takeaway for small fleets

Diesel at $4.48 and crude above $100 per barrel reset the cost floor for every load. Carriers running spot freight should factor the current pump price into rate negotiations immediately — waiting for fuel surcharges to catch up means eating the difference. Contract carriers should verify that their fuel surcharge tables adjust weekly and are indexed to a current DOE average, not a lagged or capped figure. For fleets with tight cash flow, the next two weeks are critical: if the Strait remains closed and crude holds above $100, fuel costs will stay elevated into June, compressing margins on any freight booked at pre-spike rates.