Weekly retail on-highway diesel prices released by the Energy Department Oct. 7 show the national average cost of diesel increased to $1.46 from last week's average price of $1.438. The price increase marks two months where the cost of diesel has risen.

The highest prices nationally are in California. Diesel there costs $1.569 per gallon on average. The lowest average prices are in the Lower Atlantic region. Fuel there is $1.424 per gallon.

The remaining regions' price per gallon is as follows: East Coast, $1.448; New England, $1.48; Central Atlantic, $1.497; Midwest, $1.458; Gulf Coast, $1.43; Rocky Mountain, $1.494; and West Coast, $1.534, respectively. The Department of Energy reports the average price of self-serve each week. Prices are based on a survey of 350 diesel service centers nationwide and include taxes.