I do about 70% highway driving. I used to run 5w30 but my usual was sold out last time I needed an oil change, so I went with the Rotella, which has served me well in other applications before. I got a lot of heat on here and elsewhere for that choice, though, which is why I decided to get a UOA, to make sure I hadn't made a complete botch of things. Looks like it's not a problem, though!