Prices for diesel fuel and the diesel exhaust fluid (DEF) required for operating selective catalytic reduction (SCR) emission control technology stayed relatively flat as 2012 drew to a close, while gasoline prices surged just as the New Year got underway.

According to data tracked by the Energy Information Administration (EIA), diesel prices steadily declined over the last three weeks of 2012, falling from a U.S. average of $3.945 per gallon during the week of Dec. 17 to $3.923 by Christmas and $3.918 by New Year’s Eve. However, the EIA noted that the current U.S. average for diesel is 13.5 cents per gallon higher compared to the same time period in 2012.

The agency noted that diesel prices dropped in five U.S. regions this week, increased in four of them and stayed unchanged in one. The Rocky Mountain region witnessds the largest week-to-week drop in diesel, it added – a 4.5 cent decline to $3.746 per gallon.

In terms of DEF, according to data collected by Integer Research, no price movement occured at retail pumps either in the U.S. or Canada between November and December last year. The firm said the U.S. average for DEF remained at $2.79 per gallon between November and December while the average Canadian pump price for DEF remained level at 80 cents per litre over the same period – which roughly equates to US$3.17 per gallon.

Integer added that the number of truck stops offering bulk DEF at the pump will reach the 1,000-location mark by mid-February 2013 if expansion efforts remain at their current level, with new DEF pump locations now coming online at an average of more than two per day.

Finally, the firm noted that the national U.S. average for less than full truck load bulk deliveries and tote refills of DEF recorded marginal decreases between November and December, falling by one and two U.S. cents per gallon, respectively.

The pricing trajectory for gasoline in the U.S., however, is currently on a very different path. According to EIA’s data, while the U.S. average price for gasoline inched up from $3.254 per gallon during the week of Dec. 17 to $3.257 per gallon by Christmas Eve, prices shot up 4.1 cents to $3.298 per gallon by New Year’s Eve.

However, the agency noted that the current U.S. average price for gasoline is 1/10thof a penny cheaper per gallon compared to the same time period in 2012.

EIA said gasoline prices rose in seven out of nine U.S. regions this week, with the Lower Atlantic (a 7 cent per gallon spike), Gulf Coast (a 5.3 cent per gallon jump) and Midwest (a 4.8 cent per gallon surge) all witnessing the highest per-gallon price increases.