Drivers feel some relief but prices still a dollar more per gallon overall since before US-Israel attack on Iran Sign up for the Breaking News US newsletter email The average price of US gasoline fell to just under $4 a gallon on Thursday for the first time since March , following the announcement of a preliminary agreement between the US and Iran to end the war and reopen the strait of Hormuz. The development has provided some relief to drivers who have seen soaring costs amid Washington’s war with Iran . But filling up still remains more expensive than it was before the conflict began.