°®¶¹´«Ã½

WASHINGTON — Environmental officials from California and the East Coast said during a Transportation Research Board panel here that trucks still require special attention because of diesel emissions, even though such output became much cleaner from 1998 to 2010.

Diesel’s national average pump price declined 8.4 cents to $3.053 a gallon, a four-year low, the Department of Energy reported Jan. 12.

Diesel prices began the new year the same way they finished 2014, with the U.S. retail average falling 7.6 cents to $3.137 a gallon, the Department of Energy reported.

The possibility of more Mexican trucks running in the United States is still up in the air after a recent report by the Department of Transportation’s Inspector General concluded participation in a three-year pilot program was too small to yield sufficient safety data.

The trade deficit narrowed in November as U.S. petroleum imports sank to the lowest level in more than five years.

Oil fell for a third day, extending its drop from the lowest close since 2009, as record supplies from Iraq and Russia bolstered speculation that a global glut that drove crude into a bear market will persist.

Diesel prices started the new year the way they ended 2014, falling 7.6 cents to $3.137 a gallon as oil prices fell below $50 a barrel for the first time in almost six years.

The price of diesel plunged 13.8 cents to $3.281 a gallon, the lowest level in four years, the Department of Energy reported Dec. 22.

Crude oil dropped to the lowest level in more than five years Dec. 18 on concern a supply glut will worsen.