It reacts to the car breaking in front of the red car - the trick is to use radar reflections of both the red car and the one in front of it, which propagate below the red car. This feature was advertised with a recent firmware update.
I live in Dubai and it is a mix of many cultures and people drive like crazy here, I have seen a single accident involving 6 cars because most of the rash drivers will drive tail-gating
At least Dubai really needs lot of Tesla cars to avoid such accidents which are very common here