 I purchased my Prius new during the warm weather in Maine. Gas mileage is great in temps above 50 degrees, especially on the winding hilly back roads of Maine (50 mpg). During short trips in winter it drops to 30 mpg. Original tires are quiet and help gas mileage but lasted 21K. I chose to go with a different but harder tire-which should last longer but has SIGNIFICANTLY decreased gas mileage to 30-45 mpg. Highway driving averages 42-43 mpg but this auto is very light weight and stability is compromised when driving in windy conditions or when speed reaches above 80mph. The cost to maintain this auto is above average. 