This is really cool news. I currently live in Iowa and this Winter has been terrible so far. In my area (Quad Cities) they are predicting we'll be low on salt again.
Last year we ran out towards the end of the year. The roads quickly went from bad to worse. Any company that's willing to donate salt for this purpose is a big winner in my book.
I think it's worth noting that the headline (and by that, I mean the one on Treehugger) is a bit misleading--the maintenance crews are adding the garlic salt to road salt, not simply pouring garlic salt on the roads.
That's not to say this isn't swell, though--not only is that garlic not going to end up in a land fill, there will be a cost savings given that the current stock of road salt will last longer.
We have herb salt (for general seasoning in cooking and at the table) and dried garlic here, but I'd never come across the combination.
pchristensen already answered your question but I'll add that I've lived in various parts of the UK and didn't encounter it there, either. Admittedly, it's possible I've missed it, but if so I suspect it's a niche product.
Last year we ran out towards the end of the year. The roads quickly went from bad to worse. Any company that's willing to donate salt for this purpose is a big winner in my book.