Gas was .10 cheaper in Idaho so we filled up the car there too . Our goal was to drive to Superior , MT . We got on the road at 8:30 after dinner and tried to drive the rest of the 116 miles . Immediately after Coeur D'Alene I-90 turns slow , dark , and curvy .

Answer the following question: What may be the reason to get gas in Idaho ?
The gas was cheaper .