US Gas Prices Hit $4+ as Iran War Triggers Biggest Oil Supply Shock in History

The March 2026 energy shock is the largest supply disruption on record, per the International Energy Agency. U.S.-Israel military strikes on Iran in late February triggered Iranian attacks that halted tanker traffic through the Strait of Hormuz, forcing Gulf Arab producers to cut output due to onshore storage saturation. Result: Brent and WTI posted their largest monthly gains since futures inception (1988 and 2020 respectively), with oil up >50% in weeks.

Nationwide U.S. gasoline reached $4.018/gallon (AAA data), +30% since the strikes and the highest since August 2022. Diesel crossed $5/gallon on March 17 and remains +40% higher, directly threatening freight economics. March gasoline prices are tracking +25% month-over-month—the biggest such jump since October 1990 (Macquarie).

The Trump administration’s response is multi-pronged but limited by the physical bottleneck:

• Coordinated SPR release of 400 million barrels globally (172 million from U.S. reserves).
• EPA temporary waiver on E15 ethanol blends (effective May 1–20, extendable).
• 60-day Jones Act waiver allowing foreign vessels to move product domestically.
• Signals of additional diesel supply measures and potential federal excise-tax suspension (18¢/gal gasoline, 24¢/gal diesel).

Vice President JD Vance, Energy Secretary Chris Wright, and EPA Administrator Lee Zeldin publicly frame the spike as “temporary” and war-duration dependent, while acknowledging near-term pain. Analysts (GasBuddy’s Patrick De Haan, Lipow Oil’s Andy Lipow) note the diesel lag will hit supermarkets, e-commerce, and goods prices by April, “igniting additional inflation.” De Haan warns prices could test $5/gallon absent rapid Hormuz reopening—“a race against time.”

The shock is not a marginal OPEC+ cut; it is a hard physical stop on the world’s single most important oil artery. Policy levers blunt the edges but cannot refill the Strait. Consensus pricing in a quick post-war normalization is the dominant market view; the data in the story suggest that bet is already being stress-tested.