The national average price for a gallon of diesel fuel fell four cents to $2.811 for the week ending April 29, according to the Energy Information Administration. The largest decrease was in the Midwest, down 5.6 cents to $2.775.

Prices didn’t fall in all regions however. The Rocky Mountain region logged the largest increase—one cent to $2.988.

The cheapest region in which to fill up was the Lower Atlantic, where prices fell 5.5 cents to $2.762. Conversely, California retains the dubious honor of being the most expensive place in which to fill up, in spite of a 1.7-cent decline to $2.987.

For more information, go to http://tonto.eia.doe.gov/oog/info/wohdp/diesel.asp