This Week, For The First Time Since March 12th, The National Average Price Of Unleaded Gasoline Has Dropped Below $3.50 A Gallon. And That Is Helping Keep Gas Prices Lower As Well In The Tri Cities Area. Stephanie Milani Attributes The Lower Gas Prices To A Healthy Domestic Oil Supply Which Help To Offset Fluctuations In Demand During The Busy Summer Travel Season. This Week, The National Average Price Of Gas Is $3.47 And $3.24 In Tennessee. The Average Price Being Paid By Tri Cities Motorists This Is Week Is $3.16, Down From $3.20 Just A Week Ago. AAA Officials Believe Gas Prices Will Likely Continue Their Downward Trend A Bit Longer.