ROCKFORD, Ill. (WTVO) — Rockford residents may have needed to dig a little deeper into their pockets if they filled up their gas tanks on Monday.

The average for a gallon of regular gas is up nearly 12 cents from last week. Drivers in the Rockford area are now paying about $4.39 per gallon, according to GasBuddy.

Experts said that oil prices are currently driving gas prices up, but the real issue is diesel, which is at its highest level ever. The rising cost of diesel could trickle down and be felt at the grocery store, or any place where goods are brought in by semi-trucks.