Average U.S. retail pump prices for both diesel and gasoline increased this week, according to data tracked by the Energy Information Administration (EIA), ahead of the Thanksgiving holiday when travel by automobile is only expected to drop slightly from last year’s volume.

Diesel prices increased 2.2 cents to an average of $3.844 per gallon for the U.S. this week, though that’s 19 cents per gallon cheaper compared to the same week in 2012, according to the EIA’s numbers. Diesel prices rose in all regions of the country except for the Rocky Mountains and West Coast, where prices stayed flat.

The agency noted that diesel exceeded the $4 per gallon mark in California ($4.023) and New England ($4.003) while the Midwest reported the largest one-week jump in diesel prices, some 3.5 cents to reach $3.829 per gallon, followed by the Central Atlantic (2.9 cents to $3.919) and Lower Atlantic (2.9 cents to $3.808) regions.

Gasoline prices surged 7.4 cents to $3.293 per gallon, EIA noted, though that’s 14.4 cents cheaper per gallon compared to the same week in 2012. Prices increased in all regions of the nation except for the Rocky Mountains (a 3.8 cent drop to $3.145 per gallon) and the West Coast (a one cent decline to $3.457) even when California is cut out of the West Coast’s pricing mix (a 4/10ths of a penny decline to $3.302).

The Gulf Coast and Lower Atlantic regions witnessed the biggest one-week jump in gasoline prices, EIA said, with increases of 13.6 cents to $3.14 per gallon and 13.5 cents to $3.338 per gallon, respectively. As a result, the East Coast as a whole experienced a 10.4 cent increase in gasoline prices to $3.386 per gallon, the agency noted.

Those diesel and gasoline price spikes are occurring ahead of what’s expected to be significant highway traffic over the Thanksgiving holiday, though slightly less than 2012’s volumes, according to projections by AAA.

The group expects 43.4 million people to travel in the U.S. during the Thanksgiving holiday period, a decrease of 1.5% from the 44 million who traveled last year, with the highest volumes traveling tomorrow, on Wednesday Nov. 27, the day before the holiday (37%), with the bulk returning on Sunday Dec. 1 (33%) with another 24% expecting to return on Monday, Dec. 2, or later.

AAA added that 90% of Thanksgiving holiday travelers or 38.9 million are expected to go by automobile, and while that’s a decline of 1.6% from 2012, the average distance traveled is expected to jump to 601 miles, an increase of 2.2% from 2012 when travelers planned to log 588 miles.