Traffic jams ruin driving and make life miserable for everyone, but most of all, people who actually like to drive. That MIT professor might have a solution for pointless traffic jams, but it's probably only going to work if your car has some kind of adaptive cruise control system. And apparently there's going to be something of a learning curve for that.
I think radar-guided cruise control is great, in theory. It's disconcerting if isn't not in regular use, too. But neverwander sees the biggest problem, and it's not with the radar part:
Another hurdle: Teaching people what cruise control is. I swear, no one uses cruise control on the highways. Yet it is by far the most efficient thing you can do. I am so tired of getting stuck behind people who constantly fluctuate their speed.
But I agree more with DirtyVDub as far as the fuel savings is concerned:
Cruise control is not the most efficient way to drive for max MPG. It does exactly the wrong things at the wrong times. Doing up hills you want to slow down a touch (if not in traffic) or increase power output gently. Going down hills you want to let the car speed up a bit.
Using manual control over cruise I can save 10% in rolling hill terrain. Think Iowa. In the mountains I can save significantly more especially in a turbo car by keeping it out of boost.
It's usually only on very long trips or on very heavily monitored stretches of road that I set the cruise control. It's mostly out of habit, though, since my right foot has nothing to do otherwise. But I'm all for solving traffic jams.