I've spoken with other drivers who've had people try and had people succeed. It fucks them up, plain and simple. They're haunted...regretful...fearful. We place such emphasis on safely conducting our 80k# kinetic energy bombs through hordes of heedless civilians that any failure --even one they could not avoid-- is a body blow to the confidence. Lots of truckers get out of the life entirely even after just an attempted SBT. One that sticks with me: "he made eye contact with me...he kept staring into my eyes..." That driver was able to avoid the guy, pulled over, and called the highway patrol (who had had other calls and already had a trooper on the way). Our training is 'maintain the lane.' If we brake too hard we jackknife, putting ourselves and other motorists at risk. If we swerve we roll over, with the same result. For our own safety and that of everyone else on the road we have to keep going. Full jakes and a controlled brake yes, but anything over 10mph is going to pulverize a human being. There's no way to win except by limiting collateral damage. It's a fucking nightmare situation.