Someone at Daimler/MBZ had a dream about 'wouldn't it be nice if driver reaction time was reduced when maximum braking was needed--that few feet saved might make a non-accident out of an accident'---- and SBC was born--as the first step toward fully automated braking (and spacing ) control. Well, if you have the budget of NASA, and are willing to accept the fatality rate of space program (+/- 8% death rate for astronauts), then lots of things are doable.

Unfortunately, mass produced automobiles , in everyday driving service, are not a viable platform for such sophisticated (and marginally beneficial) technology. THe cost/benefit analysis MUST have been 'cooked' to allow it. The failure rate analysis must have been a 'dream-world' analysis rather than a real-world failure analysis. I know how difficult and costly it is to get industrial process control systems to meet <1 in 10 million failures. Now--imagine--say there is 500,000 of the cars on the road everyday, and brakes are applied a total of 5 times per trip, 2 trips/day(to-from) Thats 5 million brake applications/day and therefore one could expect (of a 1 in 10 million system) a brake failure every other day. Failure could be benign or total. Now extrapolate that to 50 million vehicles--that's 50 failures/day and one would expect a significant portion to be total brake failure leading to accidents--both minor and major, depending on speed.

For a single car, it may mean you could expect (assuming 1000 trips/year, 5 brake applications/trip) a brake failure every 200 years--which seems quite acceptable. However, an automotive system like SBC is highly unlikely to reach even a <1 in 100,000 failure rate when new,considering the lack of routine performance testing of the system with off-line diagnostic tools. This leads to an expected failure rate of once/20 years. Still not too bad---but things deteriorate, and there is no programed preventive/renewal maintenance requirement like there is for industrial safety systems because it would be extremely costly (several thousands of dollars/ test and inspection/renewal) probably. So after 3-5 years, the failure rate may well be up to 1 in 10,000 or even higher. That is a failure every other year--with say 50% resulting in a collision from no brakes. hardly a comforting thought.

In summary, SBC is a great idea hunting for a need. A lot of very expensive hardware and software with really limited potential benefits, and lots of downside exposure when failure rates escalate as the system ages.