I've never driven a car with auto braking. I've been yapped at many a time for lane "departures" that were not lanes (concrete grooves on the highway being the primary culprit) and sometimes not even real (that "lane" is the shadow of a nearby power wire.) I've also seen the adaptive cruise control appear to fail once when two cars simultaneously changed into my lane, one from each side. It still had a moment it could have acted so I can't conclusively say it failed. It also fails to recognize cars with too great a speed difference.