Drivers in half of U.S. states are enjoying average gasoline prices below $3 per gallon this Thanksgiving holiday, and prices at the pump are set to further decline going into Christmas. Lower crude oil prices, cheaper winter blends, weaker seasonal demand despite the bump in Thanksgiving travel, and refineries completing autumn maintenance have converged to push the national average down to $3.055 per gallon of regular gasoline on November 25, just as millions of Americans are hitting or preparing to hit the road. The national average price of…