Idaho's gas prices have jumped 5.5 cents a gallon in the past week, AAA Idaho reports, pushing the state's average price up to $3.855, a penny higher than the national average of $3.843. A month ago, Idaho's average price for a gallon of regular gasoline was 12 cents below the national average; since then, it's risen 28 cents a gallon. Still, AAA Idaho notes it could be worse: Nine states currently have average prices above $4 a gallon, including Oregon at $4.04 and Washington at $4.06/Eye on Boise.

Question: How high do gas prices have to go before they affect your driving habits?