Something i have noticed that will also hurt the mpg is the collision mitigation doing moderate braking when i'm 200 ft behind a slower moving vehicle. Then when i change lanes it rapidly accerates to reach the set speed. It does this even when set to follow the closest. This is not very smart. I wish i could set my cms to only be active when an emminent collision is detected. I really takes away from the cars efficency in traffic. Also can be dangerous when it brakes unexpectedly when i am cutting into traffic. This system gets a thumbs down from me.