AFAIK the maximum speed differential between the Model S and an object in front of the car is 25 mph for automatic emergency braking. Any differential more than this and you will still hit the object in front of you (although at a much lower speed than you would have without AEB). Mercedes' new system has a limit of 43 mph I believe. And this has gotten me to thinking - is 25 mph an arbitrary software limitation in the current version of Tesla's software? Is the system capable of more? Or is there an inherent hardware limitation in the current suite of sensors, or perhaps processing speed limitations - which led Tesla to cap the braking differential at 25 mph?