After several weeks of steady decline, on-highway diesel prices experienced a modest rise last week, the first in six weeks. The national average is up 1.4 cents to $3.954.

The diesel gain was only the second in the past two months. California has the most expensive prices at $4.245; the Gulf Coast was the cheapest at $3.896. Increases were not uniform, as New England and the Rocky Mountain region saw declines of 1.8 and 2.7 cents respectively.

Crude oil, which fell below the $100 per barrel mark last week, continued to decline. Crude oil for July delivery declined $1.99, or 2 percent, to settle at $97.30 a barrel on the New York Mercantile Exchange.

The falling price is due at least in part to fears of a slow-down in the economic recovery, or a "double-dip" recession, as it is known. Adding to those fears is the recent announcement that Saudi Arabia will increase oil production in July.