Americans paid the highest-ever Labor Day petrol prices as the summer driving season ended, with the national average reaching a record $4.15 a gallon, adding further strain to household budgets. AAA said roughly 40 million Americans travelled over the holiday weekend despite the elevated costs, which broke the previous Labor Day record of $3.82 set in 2012 and marked the first time the average topped $4 over the holiday period. Prices usually ease after Labor Day as demand falls, but this year's rise was driven by tension linked to the Iran conflict, which has kept crude oil near $90 a barrel amid fears over disruption to shipments through the Strait of Hormuz.

The increase poses a political problem for President Donald Trump, who promised to cut petrol prices below $2 a gallon and has pushed to expand domestic drilling, making energy costs a test of his economic record ahead of November's midterm elections. Prices varied sharply by state: California was most expensive at $5.78 a gallon, followed by Washington, Hawaii, Oregon and Alaska, while Indiana was cheapest at $3.44, followed by Texas, Oklahoma and Mississippi. Whether prices fall further will depend on crude oil trends and the trajectory of Middle East tensions; the White House had not responded to a request for comment.