In its fifth straight weekly decline, diesel prices dropped 3.7 cents this week in the Department of Energy's weekly price survey.

The national average price for a gallon of ultra-low sulfur diesel fuel dropped to $3.791 a gallon, continuing a five-week slide. Diesel prices have dropped more than 20 cents in the past month, but remain nearly 50 cents a gallon higher then a year ago.

Surprisingly, gasoline prices rose 2.9 cents this week to $3.258 a gallon, posting its first price increase in six weeks.

Predictably, diesel prices on the west coast are the highest in the country, averaging $397.8 (including California). The New England region was a close second at $3.973. The lowest prices this week can be found in the Midwest, averaging 3.706 -- just two-tenths of a cent higher than the Gulf Coast.

Oil prices, meanwhile, were up $1.66 a barrel on Tuesday, ending the trading day in New York at $101.34 per barrel.

Analysts say the price of oil climbed above $101 a barrel on Tuesday in light holiday trading on growing U.S. consumer confidence and tension in the Middle East. Prices have risen in the past week as encouraging U.S. economic news pointed to stronger future demand, the Associated Press reports. The New York-based Conference Board said its Consumer Confidence Index jumped almost 10 points from November, to 64.5. That level hasn't been seen since April and was near a post-recession peak.