Average on-highway diesel prices increased this week to $1.439 from the previous average of $1.435, according to figures released by the U.S. Energy Information Administration.

The highest price in the nation is in California, at $1.640 a gallon.

The dollar-fifty mark is still found in New England, where the average price is $1.565; the Central Atlantic region, where the price is $1.545; and on the West Coast, where the price is $1.590.

The lowest average prices are on the Gulf Coast, at $1.387; and in the Lower Atlantic region, at $1.394.

The remaining regions' prices per gallon are as follows: the Midwest, at $1.410; the Rocky Mountain region, where the price is $1.468; and on the East Coast, where the price is $1.447.