This can't possibly be a good thing. Nevermind if it works as advertised or not -- just from the very definition of what's claiming to do.
I know it certainly sounds like a good thing -- it will relieve the stress and fatigue of these slow-moving situations, leading to better reaction times, etc.
But just think about for a second. When you're at the wheel, the most you should be doing on the side is talking to people, and occasionally checking your GIS. You just should not be engaged in other attention-demanding activities like reading emails, surfing the internet, or watching movies. Period.
What's going to happen is: someone's leg's are gonna get crushed, because (foolishly or not) they walked between cars in a slow-moving traffic situation (like they always do). Because, you know, a human driver would have seen them. And then the same debates will start up all over again, completely missing the point. It's not the overall statistics of this happening, or that the driver didn't respond to the flashing red light that must have gone off in time (because they were zoned out, of course).
It's that they're pushing this inherently risky technology out there (which by definition cannot be fully validated until subjected to extensive real-life conditions), not to save us from drivers who are temporarily incapacitated at the wheel, not to warn us from approaching objects we might miss ... but to let us watch Netflix while driving.