https://cdnph.upi.com/ph/st/th/9431784555308/2026/upi/7644eea5a6268565db4d3426ca5c2a50/v1.5/Average-gas-price-hits-4-again-in-US-as-Iran-war-intensifies.jpg" /> The average price of a gallon of regular grade gasoline in the United States has again reached $4 on Monday with renewed fighting in Iran.