After five weeks of increases, diesel prices go down slightly by admin | Nov 21, 2017 The average price of a gallon of on-highway diesel went down three-tenths of a cent to $2.912 per gallon for the week ending Monday, Nov. 20. This marks the first decrease after five consecutive weeks of increases. Powered by WPeMatico Share this:Tweet Related Submit a Comment Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website Notify me of follow-up comments by email. Notify me of new posts by email.