Diesel prices were up an average of 3.8 cents per gallon this week, according to the U.S. Department of Energy, to $4.127 nationwide, while gasoline prices jumped by 6.7 cents per gallon.

The DOE's Energy Information Administration's weekly report showed diesel prices averaging more than $4 per gallon in every area of the country. Even the Gulf Coast region, which had the lowest average, stood at $4.026. The highest prices were on the West Coast at $4.343, thanks to a $4.493 average in California, an 8.4-cent spike from last week.

In gasoline, the national average was $3.843, while prices hit an average of $4.073 on the West Coast. The lowest-priced region was the Rocky Mountain region, followed closely by the Gulf Coast. Gasoline prices set a Labor Day record, thanks partly to Hurricane Isaac.

Hurricane Isaac last week managed to leave Gulf oil platforms largely untouched. More than 90% of all oil production was shut down as a precautionary measure as Isaac approached the Louisiana coast last Tuesday, but oil production in the Gulf is expected to return to normal quickly. Eleven Gulf Coast refineries were affected by Isaac-related flooding and power outages.

One good thing about higher gasoline prices -- they're driving consumers to buy more fuel-efficient new cars and trucks to replace aging vehicles, with auto makers reporting better-than-expected August sales, and the auto industry is a major driver of truck freight.