Samsara Fuel Spend Index

National fleet diesel rose for a sixth consecutive week, up 5.6% to $6.28 — the highest level in the six years covered by the Samsara Fuel Spend Index, 13% above the June 2022 peak of $5.57. Gasoline rose 4.2% to $4.66. Diesel is up 76% year over year and 69% since the last full week before the conflict began in late February, when fleets paid $3.71. This is the third straight weekly all-time high.

The increase has built through the summer. Diesel averaged $5.40 in August, up 9.9% from July, and has risen a further 21% since. The two largest single-week gains of the run came in the two most recent weeks, +$0.28 and +$0.33. The index now sits 15.4% above the April 6 spring peak that had defined this cycle until late August.

Gasoline hasn't followed. At $4.66 it is up 42% year over year but still 13% below its June 2022 peak of $5.36. The diesel–gas spread widened for a sixth consecutive week to $1.62 — the widest ever recorded in the index, against a long-run median of $0.19 and a 2025 average of $0.28. A diesel shock specifically, not a fuel shock, that lands almost entirely on heavy-duty operations.

• Diesel: $6.28 (+5.6% WoW, +76% YoY, +13% vs June 2022 record)

• Gasoline: $4.66 (+4.2% WoW, +42% YoY, −13% vs June 2022 record)

• August monthly average: diesel $5.40 (+9.9% MoM)

• Diesel–gas spread: $1.62 (vs $0.19 long-run median; $0.28 2025 average)

• Consecutive weekly all-time highs: 3 (Aug 31–Sep 14)

WHAT CHANGED THIS WEEK

• Diesel +5.6% WoW to $6.28 — sixth straight increase, third straight weekly all-time high, and the largest weekly gain of the run at +$0.33

• Gasoline +4.2% WoW to $4.66 — also a sixth straight increase, but still 13% below its June 2022 record

• Diesel–gas spread widened for a sixth consecutive week, from $0.96 the week of Aug 3 to $1.62 — the reverse of the April–May pattern, when three weeks of compression preceded the spring peak

• Breadth: 50 of 50 states higher; average move +5.3%

• Largest movers: Maryland +10.1%, Montana +9.9%, Wisconsin +9.4%, with Ohio and Michigan above +7.6% — three unrelated regions (Mid-Atlantic, Rockies, Midwest), not a single corridor

• Diesel up 76% versus the same week last year, up from +52% on the August monthly average. No state is lower YoY; New Hampshire is the smallest gainer at +21.3%

• Fleet diesel ran $0.09/gal (1.4%) below AAA's national average for the week; fleet gasoline ran $0.26 (5.9%) above AAA regular — gasoline purchases in the base skew toward light-duty and service vehicles

External context: AAA's national retail diesel average broke its own June 2022 record the same week the fleet index did and stood at $6.23 on September 14; crude held in the mid-$80s; EIA distillate inventories roughly 13% below the five-year average; refinery utilization at 97%

WHERE PRESSURE WAS HIGHEST

• Highest diesel states: California ($7.64), Washington ($7.19), Hawaii ($7.05)

• Lowest diesel states: Alaska ($5.26), Colorado ($5.74), New Mexico ($5.98)

• 17 states above the national average; 33 below

The West Coast still holds the top of the table on the same supply structure that drove April's spike: lost California refining capacity, California's stricter fuel-blend requirements, and Pacific import lanes exposed to the Gulf disruption. What moved is the momentum. Through July and August the Gulf/Southeast corridor led the week-over-week gains; this week the largest moves came from Maryland, Montana and the Upper Midwest — a Mid-Atlantic consuming market with no refining of its own, a Rockies refining region, and a Gulf-pipeline-fed Midwest, all posting near-double-digit weeks at the same time. Three unrelated basins moving together is the signature of a national distillate balance problem, not a regional outage.

WHAT THIS MEANS

In 2022 the record week was followed by an immediate retreat, and the diesel–gas spread had already begun compressing before the peak printed. Neither condition is present this week: the spread widened for a sixth week and the weekly gain was the largest of the run.

The external read agrees. AAA's national retail diesel average has kept climbing since the record — $6.51 as of September 21, so W38 opens from a higher base. Crude has held in the mid-$80s through the entire run. EIA distillate inventories are roughly 13% below the five-year average heading into heating season, refinery utilization is at 97% with no throughput left to add, and EIA now assumes distillate cracks above $2/gal through November.

Pass-through is mechanical and lagging. Contract freight recovers diesel through fuel surcharges indexed to the DOE weekly average, typically one to two weeks behind the pump. Spot freight carries no surcharge line, so small carriers and owner-operators running spot absorb each week's increase until rates reprice. Private fleets carry it into delivered-goods cost. With the index setting a new record every week, every surcharge schedule in the market is behind where fuel actually is, and the gap widens with each print.

Consumers will feel this as freight, not fuel. Fleet gasoline is 13% below its 2022 record and AAA retail regular is around $4.15 against a $5.02 record — households are not seeing a record at the pump. They will see it in delivered-goods pricing over the next four to eight weeks, on the same lag the West Coast worked through in April and May.

Three things to watch in W38:

• Whether W38 sets a fourth consecutive all-time high. AAA retail was already $6.51 on September 21, $0.28 above the September 14 read.

• Whether the diesel–gas spread breaks past $1.62 or begins to compress. Compression preceded the spring peak; a first week of narrowing would be the earliest available signal of a top.

Whether the multi-region pattern holds. A repeat lead from the Mid-Atlantic, Rockies and Upper Midwest confirms a national distillate shortage; a rotation back to one corridor points to something regional.

METHODOLOGY Aggregated weekly average spend per fueling session paid by commercial customers from the Samsara Fuel Spend Index; index history begins December 2020. Pre-conflict baseline = last full week before the conflict began in late February 2026. All-time-high comparisons are nominal; on an inflation-adjusted basis the June 2022 peak equates to roughly $6.30 today, so W37 is approximately level with 2022 in real terms. YoY compares the same week 364 days earlier. All calculations use settled W37 figures (week of September 14, 2026). AAA retail averages and EIA inventory and utilization data referenced as cross-checks where noted. September figures reflect two of four weeks settled.

May was the first month of meaningful de-escalation in the macro setup that had driven fleet prices higher since late February. The Iran conflict moved toward a durable ceasefire over the course of the month, the Strait of Hormuz reopened to tanker traffic, and crude eased from the high-$80s back into the low $80s/bbl by W21. EIA distillate inventories, which had been running roughly 6% below the five-year average through April, began rebuilding as Pacific import flows resumed. The West Coast supply story — Phillips 66 Wilmington still offline, Valero Benicia idled in early April — did not resolve, but the global setup around it loosened materially.

That backdrop is the lens for May. National fleet diesel rose 3.34% in the first week to $5.45, then declined for three consecutive weeks to close W21 at $5.22 — down 4.29% from the W18 intra-month peak. Gasoline followed the same pattern: +4.97% to $4.67 in W18, then three down-weeks to $4.51 by W21. Net for the month, diesel was −1.1% W17 close to W21 close; gasoline was +1.0%. The diesel–gas spread compressed every week of May, ending at $0.71 in W21 — the tightest of the cycle and down from $0.81 at the end of April.

The W18 print was a near-retest of the W14 cycle peak ($5.453 → $5.451) but did not exceed it. From there, breadth deteriorated each week: 40 states up in W18, 17 in W19, 12 in W20, and 3 in W21. The W21 reading of 47 of 50 states down is the broadest weekly decline of the cycle. Largest W21 fallers were Colorado −5.90%, Wisconsin −5.59%, Nebraska −5.24%, Ohio −5.11%, and Illinois −4.47%.

The geographic story this month was the Midwest. Indiana fleet diesel jumped 9.81% in W18, Michigan 9.07%, Ohio 8.84%, Illinois 8.75%, and Wisconsin 7.59% — the largest interior cluster move of the cycle. Those states then reversed: by W21, the same five names had given back most of those gains. The West Coast held its highs throughout: Hawaii printed $7.20–$7.26 every week, California $6.61–$6.84, Washington $6.03–$6.23. The state spread between highest and lowest reporting state widened to $2.50 in W21 — the widest of the cycle.

• Diesel (W21): $5.22 (−3.30% WoW, +58.2% vs Dec 29)

• Gasoline (W21): $4.51 (−3.31% WoW, +52.8% vs Dec 29)

• 4-week diesel change (W17 → W21): −1.1%

• Diesel–gas spread (W21): $0.71 (vs $0.35 baseline)

WHAT CHANGED IN MAY

• W18: Diesel +3.34% to $5.451; gasoline +4.97% to $4.667. New cycle high for gasoline; diesel within $0.002 of the W14 high

• W19: Diesel −0.07% to $5.447; gasoline −0.53% to $4.642

• W20: Diesel −0.96% to $5.395; gasoline +0.41% to $4.661

• W21: Diesel −3.30% to $5.217; gasoline −3.31% to $4.507

• Diesel–gas spread tightened every week: $0.78 → $0.80 → $0.73 → $0.71

• Breadth deteriorated every week: 40 / 17 / 12 / 3 states up

• Largest W18 movers (diesel): Indiana +9.81%, Michigan +9.07%, Ohio +8.84%, Illinois +8.75%, Wisconsin +7.59%

• Largest W21 movers (diesel): Colorado −5.90%, Wisconsin −5.59%, Nebraska −5.24%, Ohio −5.11%, Illinois −4.47%

WHERE PRESSURE WAS HIGHEST (May average, W18–W21)

• Highest diesel states: Hawaii ($7.22), California ($6.75), Washington ($6.15), Indiana ($6.04), Illinois ($5.98)

• Lowest diesel states: Mississippi ($4.94), Alabama ($4.96), Minnesota ($4.98), Texas ($4.99), North Dakota ($4.99)

• Highest gasoline states: California ($6.18), Washington ($5.78), Hawaii ($5.77), Nevada ($5.36), Alaska ($5.33)

• Lowest gasoline states: Texas ($4.15), Mississippi ($4.17), South Carolina ($4.20), Georgia ($4.20), Kansas ($4.23)

• Diesel state spread (May avg): $2.28 — HI to MS

• Gasoline state spread (May avg): $2.03 — CA to TX

Note the Midwest signature: Indiana and Illinois both made the diesel top 5 for the full month, driven by the W18 spike. Neither appears in the gasoline top 5 — the Midwest pressure was distillate-specific.

The Midwest spike-and-fade was the cleanest one-month round trip the data has shown. The five states that ran hardest in W18 (IN, MI, OH, IL, WI) were all in the top five fallers by W21. Through April, those same states had been among the largest interior decliners; the W18 surge was the catch-up move, and W19–W21 was the unwind. The West Coast did not participate in either direction — California, Hawaii, and Washington held above $6.00 every week of May.

WHAT THIS MEANS

Four consecutive weeks of national diesel softening, with breadth widening to 47 of 50 states by month-end, is the first sustained ease since the cycle began. The W18 print failed to break the W14 high and the subsequent three-week sequence is structurally weaker than the W14–W17 setup that preceded April. The macro setup loosened in line with prices — the ceasefire holding and the Strait reopening removed the bid that had carried diesel through April.

Cumulative magnitude is still intact. Diesel ended May +58.2% above the Dec 29 baseline, gasoline +52.8%, every state still up 50%+ YoY. Pass-through to consumers from the February–April run-up has not finished working through the system.

The West Coast story is unchanged. Hawaii, California, and Washington did not ease in May. The state spread at $2.50 in W21 is the widest of the cycle. Any national relief in May is mechanical — interior states pulling the average down while the coasts stay flat. Until Wilmington and Benicia come back, Pacific-facing fleets and the households they serve remain disconnected from national-level relief.

The diesel–gas spread compression is the cleanest forward signal. Four straight weeks of narrowing puts the spread at roughly 2x baseline ($0.71 vs $0.35), down from >3x in early April. This is consistent with middle-distillate-specific tightness genuinely receding, independent of headline price levels.

Three things to watch in June

1. Whether the Midwest stabilizes or keeps falling. A continued slide in IN, OH, IL, MI, WI through June would confirm the W18 surge was a one-shot catch-up that is now fully unwound. Early read: national diesel fell another 2.36% in W22 and 2.31% in W23, extending the streak to six straight down-weeks. Breadth has remained negative, consistent with the interior continuing to give back its W18 gains.

2. Whether the West Coast finally eases. As long as HI/CA/WA hold above $6.00, the national decline is interior-driven and the structural setup hasn't changed. Early read: national gasoline is down 3.64% (W22) and 2.49% (W23), but the persistent Pacific premium and unresolved Wilmington/Benicia capacity loss mean coastal relief is unlikely without supply-side news. Watch for the first week HI prints under $7.00 or CA under $6.50.

3. Whether the diesel–gas spread breaks $0.70. A sustained move under would be the strongest signal yet that distillate-specific tightness is over. Early read: the W21 low of $0.710 did not hold. Spread reopened to $0.750 in W22 and $0.741 in W23 — diesel is now falling slower than gasoline, the opposite of May's pattern. This is the first sign that gasoline-led weakness is doing more of the work than middle-distillate easing. If the spread climbs back above $0.80, the May compression story is effectively done.

METHODOLOGY Aggregated weekly average spend per fueling session paid by commercial customers from the Samsara Fuel Spend Index; baseline = week of Dec 29, 2025. All calculations use settled W18–W21 figures (weeks of May 4 through May 25, 2026). AAA state-level retail averages and EIA distillate inventory data referenced as cross-checks where noted.

National fleet diesel reaccelerated this week, up 3.64% to $5.31, breaking the two-week pullback that had taken prices off the W14 cycle peak. Gasoline jumped harder, up 5.75% to $4.44, its largest weekly gain since W10 and a new cycle high that surpasses the prior W14 peak. The diesel–gas spread compressed for a fourth consecutive week to $0.87, the tightest of the cycle, as gasoline outran diesel on the rebound. Early W18 data already shows diesel at $5.65 (+6.25%) and gasoline at $4.65 (+4.79%) in the first-day read — diesel has now broken decisively above the W14 high.

Last week we framed the W15–W16 declines as lagged pass-through from earlier contracted supply, not a forward signal of relief, and warned W17 could give some of it back if wholesale conditions held. They did, and W17 gave all of it back and then some. The W15–W16 decline was a correction within an uptrend, not a topping pattern. From the W14 high of $5.49 to the W16 low of $5.15 to W17's $5.31 and W18's first-day $5.65, diesel has now made a clean higher-high after a 6% drawdown-and-recovery, and the cycle is reasserting.

The bigger story this week was the rotation. The geographic leaders flipped: the Pacific-facing states that drove W16's record state spread pulled back, with Hawaii (−$0.10), Delaware (−$0.09), and Maryland (−$0.02) the only three states down on the week. The interior states we flagged as likely to see relief reverse — North Dakota, Nebraska, Wisconsin, Oklahoma, Alabama — are all back among the largest WoW gainers. The repricing wave we tracked moving east into W14 and pulling back in W15–W16 is now reasserting inland. The state spread narrowed to $2.45, down from W16's cycle-wide $2.65, as the coasts cooled and the interior caught up.

• Diesel: $5.31 (+3.64% WoW, +58.1% vs Dec 29)

• Gasoline: $4.44 (+5.75% WoW, +47.0% vs Dec 29)

• 3-week diesel change (W14 → W17): −3.0%

• Diesel–gas spread: $0.87 (vs $0.35 baseline)

(Note: Last week's preliminary diesel of $5.15 settled to $5.13 — a $0.02 downward revision. W14 settled to $5.48 and W15 settled to $5.30. This week's WoW is calculated from the settled W16 figure.)

WHAT CHANGED THIS WEEK

• Diesel +3.64% WoW to $5.31 — first weekly increase in three weeks, breaking the W15–W16 decline

• Gasoline +5.75% WoW to $4.44 — largest weekly gasoline gain since W10 and a new cycle high, surpassing the prior W14 peak

• Diesel–gas spread compressed to $0.87, down from $0.95 in W16 and the W14 peak of $1.16 — fourth consecutive week of narrowing

• Breadth was overwhelming: 47 states up, 3 down — the inverse of last week's mixed picture (28 up, 22 down)

• The three states that fell were the most expensive coastal markets: Hawaii (−$0.10), Delaware (−$0.09), Maryland (−$0.02) — high-side mean reversion after running hardest in prior weeks

• Largest interior gains: Maine +$0.42, Nebraska +$0.40, Wisconsin +$0.39, Michigan +$0.37, Colorado +$0.35— the W15–W16 interior declines have fully reversed, confirming last week's call that they were contract-priced lag

• California fleet diesel pulled back to $6.75 from W16's $6.56 — settling above $6.50 confirms the West Coast structural story but the absence of further escalation suggests the California repricing wave has passed peak intensity

• Early W18 data: diesel $5.65 (+6.25% WoW), gasoline $4.65 (+4.79%) in the first-day read — diesel now 3.1% above the prior W14 high

• External context: Strait of Hormuz remained closed, Iran ceasefire negotiations stalled, crude held above $89/bbl, distillate inventories ran ~6% below the five-year average — the structural setup we flagged last week as not having loosened is now reasserting in the spend data

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Hawaii ($7.28), California ($6.75), Washington ($6.39)

• Lowest diesel states: North Dakota ($4.83), Oklahoma ($4.99), Alabama ($5.00)

• National state spread: $2.45 — narrower than W16's cycle-wide $2.65 as coastal markets pulled back and interior caught up

The interior reassertion was the cleanest signal of the week. North Dakota, Nebraska, Wisconsin, Oklahoma, and Alabama — the five states that posted the largest interior declines in W16 (each down 7–9% on the week) — are all back among the largest WoW gainers in W17. That confirms the W15–W16 ease in those states was contract-priced supply working through, not a real shift in fundamentals. California's pullback to $6.75 from W16's $6.56 + early-W17 surge is the mirror image: the West Coast structural premium is holding above $6.50, but the magnitude of repricing has slowed. The Phillips 66 Wilmington and Valero Benicia capacity losses (~284K bbl/day combined) remain in place; California's $1.43 premium to the national average is structural and persistent, but it is no longer the single dominant story it was in W16.

WHAT THIS MEANS

W17 closes a clean three-week round trip and confirms the W15–W16 decline was a correction within an uptrend, not a topping pattern. Diesel printed $5.49 (W14) → $5.30 (W15) → $5.13 (W16) → $5.31 (W17), and W18's first-day read of $5.65 has already broken the prior W14 high. The thesis we should retire: that diesel's structural premium would insulate it from crude on a weekly basis. It didn't in W15–W16, when diesel fell harder than gasoline in percentage terms. The thesis to carry forward: structural drivers (West Coast refining capacity, distillate inventory deficits, freight demand inelasticity) reassert on top of crude over multi-week timeframes, not against it on a weekly basis.

Cumulative magnitude has rebuilt: diesel is +58.1% above the Dec 29 baseline (up from W16's +56.4% but still below the +67.5% W14 peak), with W18 WTD already pressing higher. The diesel–gas spread at $0.87 is the tightest of the cycle but still 2.5× the $0.35 baseline. Every state remains higher year-over-year, with an average YoY increase of +$2.02 and Oregon leading at +84.9%.

The forward picture has flipped from last week's read.

• Interior pass-through is reasserting now. The W15–W16 ease in ND, NE, WI, OK, AL has fully reversed; households and small businesses in those states should expect the relief they saw two weeks ago to disappear from food, freight, and goods pricing through mid-May.

• West Coast has passed peak repricing intensity. California holding above $6.50 without extending higher, and Hawaii, Delaware, and Maryland actually pulling back, suggests the coastal repricing wave we tracked through W14–W16 is now in digestion mode. Coastal pass-through to consumers continues but at a slower marginal rate.

• The diesel–gas spread compression has changed character. In W14–W16 it compressed because diesel fell faster than gasoline; in W17 it compressed because gasoline rose faster than diesel. Gasoline is now repricing higher into the structural setup, not diesel falling out of it — a different signal that argues gasoline may be entering the same repricing cycle diesel began in late February.

Three things to watch in W18:

1. Whether W18 settles above $5.50 diesel. A settlement above the prior W14 high confirms a new leg, not a one-week breakout — the early-week $5.65 read points that way but commercial pricing typically trails wholesale by one to two weeks.

2. Whether gasoline holds above $4.50 or gives back the W17 jump. A hold confirms gasoline has now entered the same structural repricing diesel has been in since late February; a give-back would mean W17's gasoline move was a one-week catch-up rather than a regime change.

3. Whether the diesel–gas spread widens back toward $1.00 or stays compressed below $0.90. Widening signals diesel reasserting on top of structural drivers; staying compressed signals gasoline-led continuation and a different dynamic for the next leg.

METHODOLOGY Aggregated weekly average spend per fueling session paid by commercial customers from the Samsara Fuel Spend Index; baseline = week of Dec 29, 2025. All calculations use settled W17 figures (week of April 27, 2026). W16 preliminary diesel of $5.15 settled to $5.13. Early W18 data referenced in forward commentary is partial-week and will revise as the week closes. AAA state-level retail averages, EIA distillate inventory data, and crude/heating oil futures referenced as cross-checks where noted.

National fleet diesel fell for a second consecutive week, down 2.91% to $5.15. Gasoline was down 1.18% to $4.21. From the W14 cycle peak of $5.49, fleet diesel has now retraced 6.05% over two weeks. The diesel–gas spread compressed for a third week to $0.95.

That's the second weekly decline since the cycle began in late February — a real shift in the rate-of-change. But the external setup tightened this week, not loosened: the Strait of Hormuz remained closed, the Iran ceasefire collapsed mid-week, crude held near $89/bbl, and EIA distillate inventories ran about 6% below the five-year average. The national fleet decline likely reflects fleets working through earlier-week contracted supply, not improving fundamentals — meaning W17 may give some of this back if wholesale conditions hold.

The bigger story this week was the geographic split. California fleet diesel jumped 27.3% in a single week to $6.56, the largest one-week state move of the cycle. Washington rose 22.8% to $6.33. Hawaii printed $7.36. AAA's California state retail average reached $7.33 the same week, and San Francisco's retail diesel briefly crossed $8/gal on April 5 — the first U.S. city ever to do so. Pacific-facing states are absorbing the closed-Strait, lost-refinery-capacity setup faster and harder than the rest of the country. The state spread between the highest and lowest reporting state widened to $2.65, the widest of the cycle.

• Diesel: $5.15 (−2.91% WoW, +56.4% vs Dec 29)

• Gasoline: $4.21 (−1.18% WoW, +42.6% vs Dec 29)

• 2-week diesel change (W14 → W16): −6.05%

• Diesel–gas spread: $0.95 (vs $0.35 baseline)

WHAT CHANGED THIS WEEK

• Diesel −2.91% WoW to $5.15 — second consecutive decline

• Gasoline −1.18% WoW to $4.21 — also a second consecutive decline

• Diesel–gas spread compressed to $0.95, down from $1.05 in W15 and the W14 peak of $1.15

• Breadth was mixed: 22 states down, 28 up — increases concentrated on the West Coast and Northeast, declines clustered in the Midwest and South

• California fleet diesel +27.3% to $6.56, the largest single-week state move of the cycle. AAA retail diesel for California averaged $7.33 the same week

• Washington +22.8% to $6.33; Hawaii to $7.36; Massachusetts +12.5%

• Largest interior declines: North Dakota −8.6%, Nebraska −8.5%, Wisconsin −7.9%, Oklahoma −7.3%, Alabama −7.1%

• External context: Strait of Hormuz remained closed, the Iran ceasefire was not extended past mid-week, crude held near $89/bbl, distillate inventories ran below the five-year average

WHERE PRESSURE WAS HIGHEST

• Highest diesel states: Hawaii ($7.36), California ($6.56), Washington ($6.33)

• Lowest diesel states: North Dakota ($4.71), Nebraska ($4.72), Wisconsin ($4.75)

• National state spread: $2.65 — widest of the cycle

California's +$1.41 single-week move was the largest absolute state move recorded in this cycle. The drivers are the West-Coast-specific story that's been building for months: Phillips 66 Wilmington offline since late 2025, Valero Benicia idling as of early April, Pacific import lanes exposed to the Strait disruption, and California fuel-blend constraints that concentrate any tightness fast. What was new this week was the magnitude — the structural setup finally caught up to fleet pricing.

WHAT THIS MEANS

National fleet spend has now declined for two consecutive weeks, but the underlying setup that drove the run-up hasn't eased — closed Strait, lost West Coast refining capacity, distillate inventories below the five-year average, sustained crude near $89. The national declines look more like lagged pass-through from earlier-week supply than a forward signal of relief.

Cumulative magnitude is intact: diesel still +56.4% above the Dec 29 baseline, gasoline +42.6%, every state higher year-over-year. The diesel–gas spread at $0.95 is still nearly three times its $0.35 baseline.

Pass-through to consumers is now bifurcated.

• West Coast pass-through is happening now.California, Hawaii, Washington, Oregon households should expect food, freight, and goods pricing to reflect this week's fleet diesel through mid-May.

• Interior may see brief ease before re-acceleration. The W15–W16 declines in ND, NE, WI, OK, AL likely represent contract-priced supply working through. If wholesale conditions hold into next week, those states are likely to see the relief reverse.

• The diesel–gas spread compression is the genuinely new feature. Three weeks of narrowing nationally suggests middle-distillate-specific tightness is incrementally easing relative to gasoline — worth watching independently of headline levels.

Three things to watch in W17:

1. Whether California holds above $6.50 or pulls back. A hold confirms the West Coast structural story is now dominant.

2. Whether interior declines reverse. If ND, NE, WI, OK print back up in W17, the W15–W16 ease was a contract-priced lag, not a real shift in fundamentals.

3. Whether the diesel–gas spread keeps compressing. A fourth consecutive week of narrowing would be the cleanest signal that distillate-specific tightness is genuinely receding.

METHODOLOGY Aggregated weekly average spend per fueling session paid by commercial customers from the Samsara Fuel Spend Index; baseline = week of Dec 29, 2025. All calculations use settled W16 figures (week of April 20, 2026). AAA state-level retail averages and EIA distillate inventory data referenced as cross-checks where noted.

Diesel spend per fueling session declined 2.63% week over week to $5.34, down from $5.49 in W15. Gasoline also declined, by 1.04%, to $4.30. W16 marks the first week-over-week decline in diesel spend since this repricing cycle began in late February, after a two-month run driven by the Strait of Hormuz closure. We're monitoring early W17 data — diesel at $5.19 (−2.92% WoW) and gasoline at $4.17 (−2.94% WoW) in the first-day read — which would mark a second consecutive weekly decline if it holds, though Monday's 6.8% crude spike on renewed Strait of Hormuz tensions has not yet had time to pass through to retail.

• Diesel: $5.34 (−2.63% WoW, +62.03% vs Dec 29)

• Gasoline: $4.30 (−1.04% WoW, +45.64% vs Dec 29)

• 3-week diesel change (W13 → W16): +3.54%

• Diesel–gas spread: $1.05 (vs $0.35 baseline)

(Note: Last week's preliminary diesel figure of $5.53 settled to $5.49 — a $0.04 downward revision. This week's WoW is calculated from the settled W15 figure.)

WHAT CHANGED THIS WEEK

• Diesel declined 2.63% WoW to $5.34 — the first WoW decline since this cycle began in late February

• Gasoline declined 1.04% WoW to $4.30 — both fuels moved lower together for the first time in weeks

• W15 settled at $5.49, slightly below the $5.53 preliminary flagged in last week's briefing, and stands as the highest weekly print in the dataset to date

• The diesel–gas spread compressed to $1.05, down from $1.15 in W15 — still 3x the baseline ($0.35)

• 8.9% of the total diesel increase since Dec 29 occurred in the last 3 weeks (W13 → W16), a marked slowdown from the W10–W11 pace

• Breadth reversed: 29 of 43 reporting states posted WoW declines versus 14 that rose, compared to 48 of 50 states up in W14

• We're monitoring early W17 (week of April 20) data — diesel at $5.19 (−2.92% WoW) and gasoline at $4.17 (−2.94% WoW) in the first-day read — which would mark a second consecutive weekly decline if it holds

• U.S. crude closed up 6.8% to $89.61 Monday as the Strait of Hormuz remained effectively closed (3 commercial transits versus hundreds normally). Heating oil futures, a middle-distillate proxy for diesel and jet fuel, rose 5%; wholesale gasoline rose 4%

Interpretation: Spend continued lower into the first day of W17 even as crude and heating oil re-priced higher on Monday, suggesting retail is working through W15's peak pricing rather than tracking daily futures. Typical retail lag of one to two weeks means the Monday crude move may not begin showing up until the second half of W17 or into W18.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Connecticut ($6.25), Washington ($6.16), Massachusetts ($6.10)

• Lowest diesel states: Colorado ($4.51), Nebraska ($4.72), Kansas ($4.81)

• National spread: $1.74 between highest and lowest states

California posted the largest single-week decline (−$1.67), followed by Illinois (−$0.49) and Colorado (−$0.43). The largest WoW increases came from New York (+$0.60), Nevada (+$0.44), and Minnesota (+$0.30). All reporting states remain up year-over-year, with Oregon leading at +76.5% and Connecticut leading in absolute terms at +$2.67.

WHAT THIS MEANS

W16 is the first week since late February in which both diesel and gasoline spend declined. The cumulative magnitude of the cycle remains fully intact — these are weekly rate-of-change shifts off an elevated base, not a reversal of the underlying repricing.

The scale of the move since late December has not unwound. Diesel spend is still +62.0% above the Dec 29 baseline. The diesel–gas spread at $1.05 remains roughly 3x its baseline level of $0.35. Every one of the reporting states is higher year-over-year, with an average YoY increase of +$1.88 and gains of $2.00 or more in roughly half the country.

• Only 8.9% of the total diesel increase since Dec 29 occurred in the last three weeks, down from the much faster repricing in W10–W11

• Week-over-week changes flipped  to predominantly negative in W16 (29 of 43 reporting states down)

• The diesel–gas spread compressed for the first time in the cycle

Taken together, these signals are consistent with a cooling rate of change in fleet spend, even as the structural drivers have not eased.

Regionally, the late-cycle picture continues to evolve. Midwest states that drove W14's inland broadening split in W16 — Minnesota and Michigan continued rising, while Illinois, Indiana, and Ohio were flat-to-down. The Northeast retained leadership at the top of the price distribution, with Connecticut, Massachusetts, and Rhode Island all holding elevated positions. The largest weekly increase came from New York; the largest decline came from California.

The forward picture is complicated by events after the W16 reporting period ended on April 19.

• Iran's Friday declaration that the Strait was open — which briefly sent oil down 11% — was walked back over the weekend

• Dozens of commercial ships that had prepared to transit remain trapped in the Persian Gulf

• Trump told Bloomberg on Monday that it is "highly unlikely" he would extend the two-week ceasefire expiring Wednesday, and confirmed the Strait stays closed "until a deal is signed"

• Monday markets repriced: crude +6.8%, heating oil +5%, wholesale gasoline +4%

Early W17 commercial fleet data does not yet show pass-through — diesel and gasoline are both continuing lower on the week — but commercial pricing typically trails wholesale by one to two weeks, so the pass-through window opens in the second half of W17 and into W18.

Three things to watch in W17's settled read:

1. Whether the early week's −2.9% diesel decline extends through the full week or reverses as the Monday crude move passes through

2. Whether breadth stays predominantly negative or flips back to positive

3. Whether the diesel–gas spread continues compressing or widens again as middle distillates reprice off the heating oil move

W16, combined with an early W17 read we're still monitoring, marks a potential inflection after 14 weeks of sustained repricing — notable, and set against a forward backdrop of renewed supply pressure that has not yet reached fleet spend.

We’ll let you know if and when it does. 

METHODOLOGY Aggregated weekly average spend per fueling session paid by customers; baseline = week of Dec 29, 2025. W15 preliminary diesel of $5.53 settled to $5.49 (−$0.04 revision). All calculations use settled figures. W16 data is preliminary and subject to settlement revisions; early W17 data referenced in forward commentary is partial-week and will revise as the week closes. External market figures (crude, heating oil, wholesale gasoline) are Monday closing prices from public reporting and are not yet reflected in the weekly retail series. 

Diesel prices rose 4.17% week over week to $5.53, a new all-time high that surpasses the June 2022 energy-crisis peak ($5.50). The four-week deceleration trend is broken — this is a reacceleration, not a plateau. Early Week 15 data shows gasoline collapsing 10.4% on crude's 7%+ drop following Iran ceasefire announcements, while diesel holds firm at −0.26%. The divergence is structural.

• Diesel: $5.53 (+4.17% WoW, +67.46% vs Dec 29)

• Gasoline: $4.37 (+2.33% WoW, +48.16% vs Dec 29)

• 3-week diesel change (W11 → W14): +9.89%

• Diesel–gas spread: $1.16 (vs $0.35 baseline)

(Note: Last week's preliminary diesel price of $5.59 settled to $5.53. This week's WoW is calculated from the settled W13 figure of $5.31.)

WHAT CHANGED THIS WEEK

• Diesel reaccelerated to +4.17% WoW, up from +2.53% the prior week — breaking the four-week deceleration trend (calculated from settled $5.31, not the preliminary $5.59)

• Gasoline increased 2.33% WoW, slowing from +2.50% — diesel WoW overtook gasoline again, reversing last week's flip

• 22.3% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since W11)

• The diesel–gas spread widened to $1.16, up from $1.02 in W13. Last week's spread compression has reversed. Early W15 data shows the spread surging to $1.60, as gasoline collapsed (−10.4% WoW) while diesel held (−0.26%). The structural divergence we describe below is already visible in the data.

Interpretation: In isolation, W13 continued the deceleration trend — diesel WoW dropped from +12.8% (W10) → +4.8% (W11) → +2.9% (W12) → +2.5% (W13). W14 broke that trend with a +4.17% WoW reacceleration, setting a new all-time high at $5.53 that surpasses the June 2022 energy-crisis peak ($5.50). The plateau thesis is not confirmed. Meanwhile, early W15 data introduces a new variable: crude dropped 7%+ on Iran ceasefire news, and gasoline followed it down immediately. Diesel did not. This asymmetry will define the next phase of the market.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Hawaii ($7.16), California ($7.01), Washington ($6.65)

• Lowest diesel states: North Dakota ($4.84), Montana ($4.95), Oklahoma ($4.98)

• National spread: $2.32 between highest and lowest states

Hawaii posted the largest single-week jump (+$0.74), while Michigan (+$0.47) and Ohio (+$0.40) also saw outsized increases — the Midwest is now seeing the repricing wave that started on the coasts. Only 2 states saw WoW decreases (Utah, Idaho), both modest. All 50 states are now positive YoY, with Oregon leading at +86.3% and Arizona at +$2.82 in absolute terms.

California note: Phillips 66 Wilmington (LA) ceased refining in late 2025, and Valero Benicia (Bay Area) is idling as of April 2026 — a combined 284,000 bbl/day of lost capacity. California's premium reflects real supply constraints, not just regulatory costs.

WHAT THIS MEANS

This week told two stories — and the second one matters more.

The W14 data confirmed what the preliminary numbers hinted at last week: the deceleration was a pause, not a plateau. Diesel reaccelerated to +4.17% WoW, setting a new all-time high at $5.53 that eclipses the June 2022 energy-crisis peak. 48 of 50 states posted WoW increases. The repricing wave is broadening inland, with Midwest states (MI, OH, IL, IN, MN) posting outsized gains.

But the real story is the forward-looking divergence emerging in W15.

The differences from 2022 are structural:

• The 2022 peak was a sharp supply-shock spike that reversed within weeks

• The current repricing has been a grinding 15-week ascent with no reversal signals — 48 of 50 states still posted WoW increases in W14

• At $5.53, diesel is already 67.5% above Dec 29; the 2022 peak ($5.50) has been surpassed

The diesel–gasoline split is now structural, not cyclical. Crude oil dropped over 7% this past week on ceasefire announcements related to Iran, and gasoline — essentially a spot-price product — followed it down within days. Early W15 data shows gasoline collapsing 10.4% WoW to $3.92. Diesel barely moved: −0.26% to $5.52. The spread widened from $1.16 to $1.60 in a single week.

Three structural drivers explain why diesel has a floor that gasoline doesn't:

• U.S. diesel inventories have been running below the five-year average. EIA projects distillate inventories ending 2025–2026 at multi-year lows — potentially the lowest since 2000.

• Refinery capacity losses — Phillips 66 Wilmington, Valero Benicia, and LyondellBasell Houston represent ~284,000+ bbl/day of permanent or semi-permanent closures that tighten the diesel market structurally.

• Diesel has inelastic demand from freight, agriculture, and industry that doesn't flex like consumer gasoline demand. Refiners have been prioritizing diesel yield because margins are better, keeping supply tight even when crude eases.

The strategic question has shifted again: this is no longer about whether prices plateau at $5.53 — it's about whether the Iran ceasefire represents a sustained crude correction or a temporary dip that diesel's structural tightness will absorb. If crude stays lower, we may see the most divergent diesel–gasoline spread environment since this repricing cycle began. The W15 data, once settled, will be the first real test of whether geopolitical relief can offset structural supply constraints.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025. W14 preliminary diesel of $5.59 settled to $5.53; all calculations use settled figures. W15 data referenced in forward-looking commentary is preliminary and subject to settlement revisions.

Diesel prices rose 2.51% week over week to $5.31, extending a 62.50% increase since year start. The four-week deceleration trend appeared intact; however, early Week 14 data already show prices surging to $5.59, a new all-time high that surpasses the June 2022 energy-crisis peak. We’ll continue to monitor throughout the week. 

• Diesel: $5.31 (+2.51% WoW, +62.50% vs Dec 29)

• Gasoline: $4.29 (+2.75% WoW, +45.31% vs Dec 29)

• 3-week diesel change (Mar 9 → Mar 30): +25.09%

• Diesel–gas spread: $1.02 (vs $0.32 baseline)

(Note: Last week's preliminary diesel price of $5.23 settled to $5.18. This week's WoW is calculated from the settled figure.)

WHAT CHANGED THIS WEEK

• Diesel increased 2.51% WoW, down from +2.97% the prior week (calculated from settled $5.18, not the preliminary $5.23)

• Gasoline increased 2.75% WoW, slightly accelerating from +2.36% — flipping the pattern for the first time, with gasoline WoW exceeding diesel WoW

• 52.1% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since Mar 9)

• The diesel–gas spread peaked at $1.02 this week; early W14 data suggests a sharp compression to $0.76, as gasoline WoW (+12.7%) far outpaced diesel (+5.4%). The gasoline repricing wave we flagged last week appears to be arriving.

Interpretation: In isolation, W13 continued the deceleration trend — diesel WoW dropped from +13.0% (W10) → +4.8% (W11) → +3.0% (W12) → +2.5% (W13). But early W14 data already shows diesel at $5.59, a +5.35% WoW reacceleration that breaks the trend and sets a new all-time high, surpassing the June 2022 energy-crisis peak ($5.50). The plateau thesis is not confirmed.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: California ($6.69), Hawaii ($6.44), Washington ($6.37)

• Lowest diesel states: North Dakota ($4.67), Oklahoma ($4.79), Wisconsin ($4.81)

• National spread: $2.02 between highest and lowest states

California posted the largest single-week jump (+$0.54), while Arizona (+$0.41) and Nevada (+$0.33) also saw outsized increases — West Coast states continue to lead. Only 4 states saw WoW decreases (Idaho, Utah, Indiana, Illinois), all modest. All 50 states are now positive YoY, with Oregon leading at +77.4% and Arizona at +$2.65 in absolute terms.

WHAT THIS MEANS

This week told two stories — and the second one matters more.

The W13 data, taken alone, supported a plateau: diesel WoW gains fell for the fourth straight week, gasoline WoW overtook diesel for the first time, and only 4 states declined. A controlled deceleration onto an elevated base.

But early W14 data has already invalidated that. Diesel jumped to $5.59 — a +5.35% WoW reacceleration and a new all-time high, surpassing the June 2022 energy-crisis peak ($5.50). The deceleration from W10–W13 now looks like a pause, not a plateau.

The differences from 2022 are structural:

• The 2022 peak was a sharp supply-shock spike that reversed within weeks

• The current repricing has been a grinding 14-week ascent with no reversal signals — 46 of 50 states still posted WoW increases in W13

• At $5.31, diesel is already 62.5% above Dec 29; at $5.59 (W14 preliminary), it's 71.1% above

The gasoline convergence is now accelerating. The diesel–gas spread peaked at $1.02 in W13 and early W14 data shows it compressing sharply to $0.76, driven by gasoline repricing at more than double diesel's rate (+12.7% vs +5.4% WoW). The "second front" we flagged last week is no longer a signal — it's underway.

The strategic question has shifted again: this is no longer about whether prices plateau at $5.30 — it's about how far above the 2022 peak they go, and whether gasoline is now entering the same repricing cycle diesel began in early March.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025. W14 data is preliminary and subject to settlement revisions.

Diesel prices rose 3.82% week over week, extending a 59.99% increase since year start as weekly gains continue to moderate from their early-March peak.

• Diesel: $5.23 (+3.82% WoW, +59.99% vs Dec 29)

• Gasoline: $4.13 (+1.52% WoW, +39.99% vs Dec 29)

• 3-week diesel change (Mar 2 → Mar 23): +23.14%

• Diesel–gas spread: $1.09 (vs $0.31 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 3.82% WoW, down from +4.82% the prior week

• Gasoline increased just 1.52% WoW, sharply moderating from +6.59% the prior week

• 50.1% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since Mar 2)

• Diesel WoW (+3.82%) again exceeded gasoline WoW (+1.52%), continuing to widen the spread

Interpretation:

The deceleration trend that began in W12 continued this week — diesel gains have dropped roughly 70% from their W10–W11 peak, and gasoline increases have nearly flattened. Prices are transitioning from active repricing to an elevated plateau.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Connecticut ($6.65), Washington ($6.33), California ($6.14)

• Lowest diesel states: Montana ($4.82), Oklahoma ($4.87), North Dakota ($4.88)

• National spread: $1.83 between highest and lowest states

Nevada posted the largest single-week jump (+$0.91), while Connecticut (+$0.57) and North Dakota (+$0.35) also saw outsized increases. Only 5 states saw WoW decreases (Virginia, Vermont, Indiana), confirming upward pressure remains broadly distributed. Connecticut leads the nation in YoY increase at +86.0%.

WHAT THIS MEANS

The headline risk has shifted. Four weeks ago, the concern was the speed of the repricing. This week, the concern is where prices settle.

• Diesel WoW gains have dropped from +14.8% (W10) to +3.8% (W13) — a clear deceleration — but on a base that is now 60% above Dec 29

• Gasoline is flattening faster than diesel (+1.5% WoW vs +3.8%), which means the diesel–gasoline spread ($1.09, up from $0.31) is now the primary margin pressure point for diesel-heavy fleets

• 43 of 48 reporting states still posted WoW increases — the repricing is slowing but not reversing

• If next week's diesel WoW drops below +2%, that would confirm a plateau; a reacceleration above +5% would signal a second wave

The strategic question is no longer whether prices are rising — it's whether $5.20+ diesel is the new normal or an overshoot that corrects.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.

Diesel prices rose 4.82% week over week, extending a 49.31% increase since year start and following two weeks of rapid escalation.

• Diesel: $5.03 (+4.82% WoW, +49.31% vs Dec 29)

• Gasoline: $4.07 (+6.59% WoW, +28.18% vs Dec 29)

• 3-week diesel change (Feb 23 → Mar 16): +36.20%

• Diesel–gas spread: $0.96 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 4.82% WoW, down from +13.16% the prior week

• Gasoline increased 6.59% WoW, also moderating from prior double-digit gains

• 80.5% of the total diesel increase since Dec 29 occurred after Feb 23

• Gasoline WoW (+6.59%) exceeded diesel WoW (+4.82%) for the first time since the acceleration began

Interpretation:

Weekly increases have slowed significantly—diesel gains dropped by roughly two-thirds from peak—but prices remain elevated following a rapid repricing period.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Washington ($6.37), Hawaii ($6.23), Connecticut ($6.22)

• Lowest diesel states: North Dakota ($4.56), South Dakota ($4.75), Nebraska ($4.76)

• National spread: $1.81 between highest and lowest states

Price pressure remains geographically concentrated, with coastal and Northeast states sustaining the highest absolute costs. The Northeast (RI, ME, CT) is now posting the steepest weekly gains, suggesting a lagged repricing wave moving east.

WHAT THIS MEANS

Fuel prices have moved through a three-phase pattern:

1. Stability (through mid-Feb): single-digit weekly changes, gradual drift upward

2. Acceleration (Mar 2 → Mar 9): sustained double-digit weekly increases

3. Moderation (Mar 16): mid-single-digit increases on a higher base

Prices are no longer just rising — they've reset higher:

• Diesel is +49.31% vs baseline

• The diesel–gasoline gap has widened from $0.20 to $0.96

• Cost pressure remains highest for diesel-heavy operations and high-cost states

• All 50 states have higher diesel prices than a year ago (+48.48% YoY nationally)

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.

Diesel prices surged 13.16% week over week — the second consecutive week of double-digit gains — pushing the cumulative increase since Dec 29 to 42.45%.

• Diesel: $4.80 (+13.16% WoW, +42.45% vs Dec 29)

• Gasoline: $3.82 (+10.76% WoW, +20.26% vs Dec 29)

• 3-week diesel change (Feb 16 → Mar 9): +33.68%

• Diesel–gas spread: $0.98 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 13.16% WoW, slightly down from +14.83% the prior week but still in double-digit territory

• Gasoline increased 10.76% WoW, roughly in line with the prior week's +10.34%

• 77.3% of the total diesel increase since Dec 29 has occurred in just the last two weeks

• All 50 states saw diesel prices rise — no state was spared

Interpretation:

This is now the second straight week of double-digit diesel gains. The acceleration that began in early March is sustaining, not fading. Prices have moved from gradual drift to a full repricing event.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Washington ($5.93), California ($5.91), Hawaii ($5.82)

• Lowest diesel states: North Dakota ($4.42), Montana ($4.45), Nebraska ($4.59)

• National spread: $1.51 between highest and lowest states

• 28 states above national average, 22 below

Biggest WoW movers: Idaho (+$0.44), Utah (+$0.43), Vermont (+$0.40). No state saw a decline — the repricing is universal across all 50 states.

WHAT THIS MEANS

The fuel market is now clearly in an acceleration phase. Two back-to-back weeks of 13–15% diesel increases have reshaped the cost landscape:

• Diesel has gained over 42% vs the Dec 29 baseline in just 10 weeks

• The diesel–gas spread has widened from $0.20 to $0.98 — nearly 5× the baseline

• The pace of increase has not yet moderated, suggesting the repricing may have further to run

• With 100% of states seeing increases, there is no geographic safe harbor this week

Diesel prices exploded 14.83% week over week — the largest single-week increase in the dataset — catapulting the cumulative gain since Dec 29 to 25.88%.

• Diesel: $4.24 (+14.83% WoW, +25.88% vs Dec 29)

• Gasoline: $3.45 (+10.34% WoW, +8.58% vs Dec 29)

• 3-week diesel change (Feb 9 → Mar 2): +19.71%

• Diesel–gas spread: $0.80 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 14.83% WoW, a massive escalation from +2.88% the prior week

• Gasoline increased 10.34% WoW, also jumping sharply from +2.46% the prior week

• 74.6% of the total diesel increase since Dec 29 occurred in this single week and the one prior

• All 50 states saw diesel prices rise

Interpretation:

This week marks the inflection point. After two months of low-single-digit weekly changes, diesel prices suddenly jumped nearly 15% in a single week. Gasoline followed with a 10%+ move. Something fundamental shifted in the market during the last week of February — the gradual drift is over and a rapid repricing is underway.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: California ($5.76), Washington ($5.63), Hawaii ($5.57)

• Lowest diesel states: Montana ($4.08), North Dakota ($4.19), Minnesota ($4.36)

• National spread: $1.67 between highest and lowest states

• 25 states above national average, 25 below — an even split

Biggest WoW movers: North Carolina (+$0.74), South Carolina (+$0.67), Virginia (+$0.67). The Southeast posted the largest dollar increases this week, with the Carolinas and Virginia leading. Biggest declines: North Dakota (−$0.36), Oklahoma (−$0.34), Minnesota (−$0.31) — Plains states bucked the trend.

WHAT THIS MEANS

This is the week the market broke. The data tells a clear before-and-after story:

• Before (Jan–late Feb): diesel WoW changes ranged from −0.4% to +3.2% — normal weekly noise

• After (Mar 2): +14.83% in a single week, with gasoline following at +10.34%

• The diesel–gas spread quadrupled from $0.20 to $0.80 in one week, signaling that diesel-specific supply factors are driving this move

• The geographic pattern is unusual — the Southeast led increases while Plains states actually declined, suggesting regional supply disruptions rather than a uniform demand shock

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.