Fuel prices in Vancouver are on the rise again, up by 4 cents this week to top $4 per gallon for regular unleaded after remaining below that level for several weeks, according to AAA Oregon/Idaho. Higher fuel prices here and across the nation indicate demand for fuel as the summer travel season wraps up, AAA said. Prices also reflect climbing crude oil prices as Hurricane Isaac entered the heart of the Gulf of Mexico’s oil and refinery operations, according to NPR. The average price of regular unleaded is $4.39 per gallon in Washington state this week, the fourth-highest price among all 50 states. In Oregon, the average price for a gallon of unleaded also is $4.39. Across the nation, the average price of a gallon of gas is $3.77 per gallon.