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navigating high-grade descents are the wrinkle - truck air brakes seem very finicky. But I think there's no reason why long, sparse, flat freeway sections could not be run by automated cabs relatively soon, for example CA-I5 from Tejon Ranch to Stockton, or the I80 between Chicago outskirts and somewhere in Wyoming.



Truck air brakes are finicky because they are mechanically designed to distribute brake pressure evenly across the wheels in response to one input -- pressure from the driver's foot on the brake pedal. An automated cab could communicate more information: desired speed, tolerance, required stopping distance, and general vehicle stability info, and a microcontroller at each wheel could combine that with sensor info about road conditions and temperature at that wheel to determine how much brake to apply and where -- all with faster reaction times than a human driver would be capable of.


The old technique was, at a wheel, hit the brakes really hard to stop the wheel rotating as fast as possible, hopefully less than one second, and then fully release the brake. Then the stopped wheel starts sliding and, then, starts rotating again, while still sliding some, until it is full rotating again, and then hit the brakes again. So, the technique is automatically sensitive to load, tread on the tires, traction on the road, etc. So, don't want all the wheels stopped at the same time. Then on an 18 wheel truck, should still be able to maintain directional control.

Of course, there is a lot that could be done, but most of that has one thing in common -- money, for the engineering, manufacturing, original purchase, in-service monitoring, problem detection, problem diagnosis, and repair. Money.


Presumably we don't spend $10k/trunk on better brakes because humans can deal without them. But if that was what's needed to make self-driving work, the economics could support it. Electric regenerative breaking would do nicely.


Sure a single air brake is finicky, but 8 hubs with individually controlled regenerative brakes? Sounds like a perfect job for a computer.




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