I didn't really mean the technology itself, more the logistics of actually making it work at scale.

Something like an embedded wire in the centerline of each lane that could be followed by a simple metal detector seems a lot simpler.

That's how GM did automatic driving for Firebird II and III in the 1960s.

Volvo's solution for snow is to drive magnets in the form of nails into the pavement along lane centerlines. They suggest that this can provide guidance for snowplows as well as assist autonomous vehicles.

Lane marking in areas of heavy snow is hard. Some areas put up plastic posts along the roadside. Japan puts up arrows hanging over the road in parts of Hokkaido.

The thing about this is, you don't have to mess with the roadway at all. It relies on the fact that subsurface features beneath the pavement don't tend to change much over time.

Embedding wires or magnets or whatever in every paved street in the world would be MUCH more complicated, not to mention economically disruptive.

Embedding a wire in millions of miles of road seems way more complicated than this.