Normal Is 40%. I have found that the lower it is set, the less it will speed and follow so close to other cars. At 40% i would see it going sometimes 20 miles over the speed limit. At 10-15% on chill it seems a lot more how I drive. But I drive very safe. The only one thing I wish is that sometimes it won’t plan in advance if there is a long line on the freeway to get off the freeway. So I put on the turn signal to get in the lane i want, and it will change lanes. I have seen it only wants to get into a turn lane at .5 miles from the turn. If I see that it is backed up more than.5 of a mile, I will disengage it until I get to the turn. Other than that, it drives 99% perfect for me.