90,000 of the 121,000 miles on my Avalon are highway and interstate miles, driving from Illinois to Tennessee to care for my ill father, and to SC to build a house. Also drove across the counry horizontally twice. Never a problem! This is a fabulous car--feels like it will go another 121,000 miles easily. The comfort has my Lexus owning friends envious. The AC is the best on any car and keeps a black car with black interios cold in August in South Carolina, with no tinting on the windows. All I do is take it to the dealership for each major service. Gets 32 mpg hwy.