Diesel fuel prices dipped again this week, while the opposite occurred for gasoline, according to data tracked by the Energy Information Administration (EIA).

By contrast, prices for diesel exhaust fluid (DEF) remained relatively flat in North America, noted global consulting firm Integer Research.

The national average retail pump price for diesel declined 7/10ths of a penny this week to $3.814 per gallon, EIA reported, which is 16.7 cents per gallon lower compared to the same week in 2013.

Diesel prices exceeded the $4 per gallon mark in California – down 5/10ths of a penny to $4.079 per gallon – and on the West Coast, which witnessed a 2 cent spike to $4.030. With California removed from the mix, diesel prices on the West Coast jumped 5.2 cents to $3.973 per gallon, the agency said.

By contrast, diesel prices declined in all other regions of the country, EIA noted, with prices falling the most in the Lower Atlantic – down by 1.5 cents to $3.756 per gallon.

The national average retail pump price for gasoline increased 5/10ths of a penny to $3.459 per gallon this week, the agency said, though that is 14.9 cents per gallon cheaper compared to the same week in 2013.

Gasoline prices increased in three regions of the U.S. while falling in the rest, the agency pointed out. Gasoline jumped the most in the Midwest, climbing 3.5 cents to $3.432 per gallon, followed by the Lower Atlantic with a 1.6 cent spike to $3.336 and the East Coast sporting a 7/10ths of a penny jump to $3.409.

The biggest declines for gasoline occurred on the West Coast – down 2.8 cents to $3.797 per gallon, translating into a 1.9 cent drop to $3.717 with California’s prices removed from the mix – and the Gulf Coast, where gasoline dropped 2.2 cents to $3.216; the lowest pump price for gasoline in the U.S. this week.

Where DEF is concerned, Integer reported that national average DEF pump price in the U.S. remained stable at $2.79 per gallon for the fifth consecutive month, while in Canada pricing remained at 80 cents per liter – roughly US$3.17 per gallon.

According to the firm’s DEF Tracker service, DEF bulk prices in the U.S. increased for full TL and LTL deliveries in August compared to July, while prices for tote refill deliveries declined by a penny per gallon.

Average 2.5 gallon jug prices decreased in the U.S. and Canada in August by six cents per gallon and by 12 cents Canadian per liter, respectively, Integer reported.