I have driven my 1998 Legacy Outback from Denver to Toronto. While in Toronto I have been going on fishing trips a few times a week. Almost all of this driving is on interstate/freeway/highway roads. I have been keeping track of my mileage and mpg every time I fill up. I do this as much to see how much gasoline is actually costing me in US dollars. I have been getting anywhere from 26-28 mpg using Costco’s lowest octane gasoline. I try to use Costco gas as much as possible. The only time I noted a significant drop in the miles per gallon was when I had to buy non-Costco gas in Nebraska. It must be something with the corn ethanol percentage in the gasoline as I noted this same thing happening when I drove my ’97 Grand Caravan to Toronto last year. I should note that my Subaru has a 5 speed manual transmission and there is nothing installed on the roof rack. I do have the back filled with fishing equipment.