As of mid-May 2026, dramatic variation in U.S. state-by-state diesel prices is directly impacting the logistics sector and supply chain. According to data from the Federal Energy Information Administration (EIA) and GasBuddy, the national average diesel price stood at $5.64 per gallon on May 11, 2026, with state prices ranging from $4.69 to over $8.00. The lowest prices are in Texas ($4.69), Louisiana ($4.84), Oklahoma ($4.85), and Mississippi ($4.86)—states that benefit from low state taxes and proximity to refineries. By contrast, California's state average has surpassed $8 per gallon, marking a historic record for diesel fuel in the United States.
The price surge stems from geopolitical tensions in the Middle East and disruptions in the Strait of Hormuz. During March–April 2026, the U.S.-Iran conflict affected this critical chokepoint that moves roughly 20 million barrels of oil daily, tightening supply and driving up crude and refined product prices. Diesel prices rose more than 50% in the first four months of 2026; the national average climbed from $3.72 per gallon in February to $5.65 in early May. Midwest states including Michigan ($6.01), Illinois ($6.01), Wisconsin ($5.84), Indiana, and Ohio recorded all-time highs due to refinery issues. Additionally, Arizona, Washington, and other West Coast states also hit record diesel levels.
The impact on transportation costs is broad and immediate: diesel accounts for approximately 20–25% of trucking operating costs. According to DAT Freight & Analytics' March report, the national average van fuel surcharge rose to 61 cents per mile—the highest since late 2022 and a 50% increase from the 2025 average of 40 cents. Contract freight rates also rose: van at $2.72 per mile, reefer $3.10, flatbed $3.43 (up 20–30 cents month-over-month). Small carriers and independent owner-operators took the hardest hit: without fuel discounts, bulk purchasing power, or surcharge protection, diesel price spikes forced some operators to "park their trucks." Logistics experts warn that when diesel hits the national threshold of $6 per gallon, consumption may begin to slow and margin pressure on food, retail, and industrial logistics will intensify.
State tax differences and local market conditions widen the price gap: Pennsylvania's state diesel tax ($0.741 per gallon) is the highest, while Alaska has the lowest ($0.089 per gallon). Though the federal diesel tax remains at $0.244 per gallon, state taxes, environmental regulations (such as California's clean-fuel standards), and refining capacity shape regional pricing. According to analysts at C.H. Robinson and Freightquote, fuel surcharge tables based on national averages create recovery gaps for carriers operating in high-price regions like California or the Northeast. Companies are focusing on fuel management strategies (apps like GasBuddy and Mudflap, discount networks, route optimization) and alternative fuel research. Yet in the short term, the existing diesel infrastructure will sustain pressure; EIA and industry sources predict diesel prices will remain elevated unless the conflict is resolved.
Note: This summary draws on SupplyChain247's publicly visible headline and on sector background on U.S. diesel prices and logistics costs.
Key Takeaways:
1. May 2026 national average diesel price stands at $5.64/gallon; state prices range from $4.69 (Texas) to over $8 (California).
2. Strait of Hormuz conflict drove diesel prices up 50%+ in first four months of 2026; Michigan, Illinois, Wisconsin hit record highs.
3. Truck fuel surcharges rose to 61 cents/mile (highest since late 2022); contract freight rates up 20–30 cents/month.
4. Small carriers and independent owner-operators hardest hit; some drivers forced to park trucks, industry anticipates demand slowdown at $6/gallon threshold.
5. State tax differences (Pennsylvania $0.741/gal, Alaska $0.089/gal) and refinery capacity widen regional price gap; firms focus on fuel management and alternative fuel solutions.
