The average retail price for diesel dropped 0.6 cents last week to $1.718, according to the Department of Energy. That breaks a six-week, 10.7-cent rising trend since March 15.

The Rocky Mountains is the only region that posted an increase, with a 4.1-cent hike to $1.876 per gallon. The Lower Atlantic region showed the largest drop, as well as the lowest average price, posting 1.3 cents and $1.611 per gallon, respectively. California once again is the most expensive region in which to buy diesel, at $2.247 per gallon.