The average price for a gallon of diesel nationally dropped four cents to $2.811 for the week ending April 29, according to the Energy Information Administration.
The Midwest, down 5.6 cents to $2.775, experienced the largest drop. The Rocky Mountain region had the largest hike-one cent to $2.988.
The cheapest region was the Lower Atlantic -- $2.762 after a 5.5-cent drop. California remained the most expensive ($2.987), despite a 1.7-cent decline.