When I saw the headline to this article, I was thinking more in terms of generated EMI. From time to time, I've thought of building an EMI "gun" that would inject electronic noise into the amp circuit, which would turn into audio noise, of passing motorists or neighbors with overly loud music.
I don't think such a device would make things any more plesent on your drive though. :-)
I seem to do a decent job of mentally filtering out most music - until it reaches a certain volume. I do use ear muffs when mowing the lawn or using loud tools of any sort, but they seem to annoy me enough that I don't think I could wear them for an eight hour drive.
Yes, I own a couple of pairs that I've picked up over the years (I managed to find them for closer to $200). Like all IEMs they require insertion into the ear canal, which not everyone is comfortable with, and which is not quite as convenient as slipping on a pair of standard headphones, but the sound quality (and noise isolation) can be amazing - especially if you do as Siegfried Linkwitz (of Linkwitz-Riley filter fame) did and add a notch filter circuit to customize them to your ears:
Why not kill two birds with one stone and try out some in-ear monitors (IEMs)? Not only do they provide great noise isolation, you can listen to your own audio content as well. The Etymotic ER-4 for example provides noise isolation of 35 to 42 dB, which is even better than those bulky earmuffs.