When i use the acc, and the highway is hilly, the acc will engage the fcm (forward collision mitigation), resulting in the brakes being applied, sometimes forcefully, resulting in an immediate slow down of my vehicles speed. this can cause accidents as those around me had to slam on their brakes as well. when going up and down hills, the acc does not work properly. this has occurred many times from the time i bought the vehicle until now.
When on the highway, i set the cruise for a set speed. with no other cars around me, my speed will vary significantly. i set the speed for 70mph (speed limit) and the car will go from 64mph and surge up to 78mph all on it's own. this has happened to me 4 times to date. once it ended in a speeding ticket when i first got the car. i was really confused how i was clocked going 79 mpg when the cruise was set on 70mph. it has occurred a number of times since, causing me to cancel the cruise control in order to normalize my speed.