Diesel fell for the second time in three weeks, dipping 1.8 cents to $4.003 per gallon, the Department of Energy reported.
The downturn was just the second in the past two months, and diesel’s two declines in mid-January were the only other declines since mid-December.
Trucking’s main fuel is 13.3 cents higher than it was in mid-December, according to DOE records.
Gasoline, meanwhile, continued its recent string of increases, rising 3.5 cents to $3.547 a gallon.
The motor fuel has risen more than 25 cents in six consecutive increases.
Diesel is now 4.4 cents below the corresponding week last year, while gasoline is 14.9 cents under a year ago, DOE said following its weekly survey of filling stations.
Each week, DOE surveys about 400 diesel filling stations and 800 gasoline stations to compile national average prices.