content: The Tesla, like the Infiniti Q50 and the Nissan Maxima can 'see' two cars ahead. If it calculates that there is likely going to be a collision between those two vehicles it gives an audible warning and, if necessary, does emergency braking. It uses forward looking radar to achieve that. (Got these links from the electrek forum) Hard to say when the automatic braking actually kicked in, the speed indicator on the dashcam footage seems to lag about a second. You see that lag best when the Tesla has come to a complete stop and the dashcam still shows 12 km/h. After watching the video again, I think the Tesla brakes instantly, as soon as the audible alarm sounds. If you look closely you can see the hood/front end moving down as the sound comes on.