Pretty much higher 9 could possibly be in the 10 mark but if you factor in the APU usage than thats where ya go back to the higher 9. Still the better deal no matter what is staying with the big trucks as the engines are use to hauling the 80,000 lbs of freight and that is like a piece of cake when we haul our little 9,000 lbs loads. The maintence is hardly any and runs like a deer, Ha, anyway love our Cascadia so thanks to our ownner we are proud to run down the hyway in style. Hope this helps!!