What the GP comment meant that the robots won't deviate from the parameters. Contrast this with a human operator, who are instructed to drive at specific speed

What the GP comment meant that the robots won't deviate from the parameters. Contrast this with a human operator, who are instructed to drive at specific speeds at each road section. Perhaps due to fatigue , overconfidence (e.g. I drove on this road 1000's times before, I know what I am doing), or other factors, the driver did not slow down enough and subsequently accidents occur.