Where fuel costs are climbing fastest—and why shelf prices are next

When pump prices dominate the news, the story almost always flows to the coasts. California clears $5.90 a gallon, Hawaii tops $6, Washington pushes past $5.40. Those numbers are eye-catching, and they deserve the attention they get.

But the pump is only the first hit. It's the immediate one — visible at every fill-up, felt in every weekly budget — and it's the one that dominates the news cycle.

The longer, larger impact is still in the pipeline, and it won't show up as a gas price at all. It will show up as a higher grocery bill, a steeper shipping charge, a bigger quote from the contractor, and a new menu price at the restaurant down the street.

Diesel moves roughly 72% of U.S. freight by truck. It powers farm equipment, construction machinery, and the trains and ships that bring in imported goods. Since the week of December 29, national fleet diesel spend has jumped 61%, a bigger move than gasoline, and that increase is now working its way through the economy as higher prices on goods that have nothing to do with the pump.

This analysis draws on the Samsara Fuel Spend Index, which measures real-time gasoline and diesel spend across commercial fueling activity in all 50 states. Because fleets fuel constantly and at scale, their spend moves faster and earlier than consumer retail benchmarks, which makes the Index an early read on where fuel-driven cost pressure is building before it shows up on the grocery shelf, the shipping invoice, or the restaurant menu.

States where fuel spend is climbing fastest

Fleet and retail prices both reflect the week of April 13, 2026. Fleet prices are derived from the Samsara Fuel Spend Index; retail pump prices from AAA.

Every state on this list started the year well below the national average for both gas and diesel fuel. Every state on this list has now seen the average price per gallon of both fuels rise faster, in percentage terms, than any of the traditionally expensive markets. The first consumer impact, the one households will feel this month, is already showing up at gas stations. The second, the pass-through from diesel into food, freight, and housing costs, is still in the pipeline.

Idaho: leading the country on combined fuel run-up

Idaho's fleet gasoline spend rose from $2.89 to $4.44 per gallon since late December. Fleet diesel spend went from $3.08 to $5.55 per gallon, an 80% jump. At the retail pump, Idaho drivers are now paying $4.26/gal for regular unleaded, up from just over $3 at the start of the year.

Idaho is a heavy agricultural state. Diesel powers the equipment that plants and harvests its potato, wheat, sugar-beet, and dairy economy. When diesel nearly doubles at the farm level, those costs move through to wholesale produce and dairy prices — not this week, but through the summer and into fall harvest. Idaho households will feel the first impact in their own tanks and the second on their own grocery shelves.

Colorado: #1 on gasoline, #2 overall

Colorado leads the nation in fleet gasoline spend increase, from $2.60 to $4.16 per gallon, up 60%. Fleet diesel spend rose from $2.93 to $4.96 per gallon, up 69%. At the retail pump, Colorado is actually one of the cheaper spots in the West at $3.94/gal, reflecting a relatively lower baseline. But the rate of change is what reshapes a monthly budget. A Colorado commuter whose fill-up cost $38 in December is paying closer to $62 now. A Colorado household that was used to spending $200 a month on gas is spending closer to $325.

The diesel side will follow. Colorado has heavy freight, agriculture, and construction sectors that all run on diesel, and all are now absorbing a roughly 70% cost increase that will eventually surface in local pricing.

Utah: a 64% jump across both fuels

Utah's fleet gasoline spend rose from $2.74 to $4.32 per gallon (up 57%), and fleet diesel spend went from $3.09 to $5.31 per gallon (up 72%). At the retail pump, regular unleaded averages $4.15/gal. Utah has the largest average household size in the country, which multiplies the pump impact: more drivers per home, more miles per week. On the goods side, Utah's fast-growing economy, residential construction pipeline, and agricultural sector all run on diesel, and all will reflect higher fuel input costs in prices paid by residents over the coming months.

Oregon: biggest diesel jump in the top five, and past $5 at the pump

Oregon's fleet diesel spend went from $3.30 to $5.95 per gallon since December, an 80% jump tied with Idaho for the largest diesel move in the top five. Fleet gasoline spend rose from $3.44 to $5.05 per gallon, up 47%. At the retail pump, Oregon is now averaging $5.00 per gallon — joining California, Hawaii, and Washington in a tier most of the country hasn't reached.

Oregon's exposure is unusual. It has no in-state refining, so every gallon sold there came through a pipeline or a truck from somewhere else. As diesel climbs, so does the cost of moving every good into the state, compounding the direct pass-through from freight rates. Oregon households also have one of the longer average commutes in the region, which amplifies the direct gas-pump impact.

Arizona: the top-five state with the highest pump price

Arizona combines a 77% fleet diesel spend jump (from $3.33 to $5.90 per gallon) with a 50% fleet gasoline spend jump (from $3.17 to $4.75 per gallon). Retail drivers are feeling it even harder: Arizona's AAA average is now $4.64/gal, the sixth-highest in the country and well past the psychological $4 threshold. The state also depends heavily on long-haul diesel freight for groceries and goods (it has minimal in-state food production at scale), which means the pass-through is both larger and faster than in more self-sufficient states.

Why these states are taking the biggest percentage hit

Five states with no in-state refineries. Five states that started the year below the national average on both fuels and are now getting pulled toward it.

The states that didn't make this list — California (gas +36%), Hawaii (+33%), Washington (+35%) — didn't escape the surge. They're still expensive in absolute terms. But they had less arithmetic room to climb off an already-elevated base. The places that started cheap are converging toward the rest.

Two waves of consumer impact

The pump wave arrives first. A household in any of the top-five states filling two cars a week is now paying roughly $150 to $250 more per month on gasoline than it was at New Year's. That's a visible line-item change, the kind households notice on the next card statement or the next trip to the station.

The diesel wave arrives second, and it's harder to see because it doesn't show up on a bill with "fuel" on it. It shows up as a 10-cent increase on a loaf of bread. A $4 surcharge on a package delivery. A steeper quote from the contractor. A higher menu price at the local diner. Federal data shows transportation is already the second-largest average household expense behind housing, and diesel pass-through feeds into all of it over weeks and months.

For households in the five states on this list, both waves are landing. Gasoline at the pump is the immediate impact. Diesel-driven price increases on everything else are the slower one, and they typically last longer than the initial fuel move itself, because pricing on goods tends to be stickier on the way down than on the way up.

What to watch

• Pump prices in the five states over the next four to eight weeks. If fleet spend eases first (as it tends to), retail pump prices follow within weeks. If fleet spend holds, pump pressure extends into summer.

• Grocery and shipping costs in the interior South and Mountain West. Diesel pass-through takes a few weeks to reach the shelf, but when it does, food, freight-heavy goods, and building materials move first.

• Small business pricing in the affected states. Contractors, local delivery services, and restaurants are the businesses most exposed to diesel input costs and the least able to hedge. Their pricing moves tend to be a leading indicator of the broader consumer impact.

• State-level policy response. Fuel tax holidays, targeted assistance, and utility relief programs tend to emerge when fleet and consumer fuel costs together cross psychological thresholds. All five states on this list are now well past them on one or both fuels.

The five states at the top of this list share something beyond geography: they're seeing both fuels spike together, which means their households will feel the run-up twice — once directly at the pump, and again through the cost of nearly everything they buy. Commercial fuel spend has already told us the second wave is on its way. The question now is how long, and how hard, it lands.

A note on methodology

All fleet spend data comes from the Samsara Fuel Spend Index, a weekly measure of what commercial fleets actually pay for gasoline and diesel, drawn from real-time commercial fueling activity across all 50 states. The Index reflects fleet fuel spend, not consumer retail pump prices, which are typically higher. AAA state-level retail averages are used here for the pump comparison. State-level fleet figures compare the week of Dec 29, 2025 (the pre-surge baseline) to the week of April 13, 2026, the most recent week with full state-level coverage at the time of analysis. The "combined average" column averages each state's percentage increase in gasoline and diesel fleet spend. Retail pump prices are AAA state averages from the week of April 13, 2026. The relevance of fleet fuel spend to consumer economics comes through pass-through: fleet-driven costs in freight, agriculture, construction, and local delivery surface in grocery prices, shipping fees, housing costs, and service rates on a lag of weeks to months.