Gas prices are trending upward in Central Indiana after a plunge earlier in the week.The average price of a gallon of unleaded regular gas, which was $1.48 on Monday, was at $1.70 today after a 7-cent jump from the price on New Year’s Day. The statewide average, which was $1.55 on Monday, was $1.67 today, according to AAA and Oil Price Information Service.PUMP PATROL: Lowest gas prices in the Indy area.Motorists may want to think of Dec. 29, 2008 as a watermark: many pumps in Central Indiana were offering gas in the low $1.30s. While IndyStar.com’s Pump Patrol shows most prices in the low $1.60s today, 58 Speedway stores in the Indianapolis area were at $1.85 today.The Web site gasbuddy.com says “real-time” prices today are $1.84, up 11 cents from Thursday.