The average price at the pump for a gallon of diesel fuel fell 1.1 cents to $1.423, according to the U.S. Dept. of Energy. According to the department's Energy Information Administration, the price is the lowest since it hit $1.401 on December 16. Drivers in New England are paying the highest average at $1.57. The lowest averages can be found in the Gulf Coast ($1.361) and Lower Atlantic ($1.389) regions.