I own a 2010 Prius III and have about 47,000 miles on it so far (I do a lot of driving, I know!). Recently, I had my tires replaced and have had the 45k scheduled maintenance completed on my car but my gas mileage has been horrible since replacing my tires. My wife and I just took a road trip to eastern Washington (where the terrain is mostly flat), and I averaged since the trip around 43 - 45 mpg. Before replacing my tires, I was getting the normal 49 - 51 mpg since April when the weather warmed up. This past winter I averaged around 46.5 - 47 mpg. The gas mileage has been AWESOME up until the recent tire replacement. I love this car, and how it's helping to reduce CO2, but it's frustrating when the mileage isn't where it *should* be! I'm wondering if anyone else has had this same issue? I've taken my car to a dealership to get this checked out, who did a quick check on the tire pressure, fluids, air filter, brakes and found nothing wrong. They basically said that unless an alert is showing on the display, there's nothing wrong with the car. But, I still have the reduction in gas mileage. The only variable is the tire replacement, which I've heard could cause more resistance on the road. If anyone has heard of this kind of issue, please let me know. Thanks!