The era of "smart cars" actually makes targeting much easier. You don't need to bulk disable cars in a country.

Imagine an enemy country using zero-days to track a military leader via their personal device(s), then disabling their smart civilian vehicle they use to commute to work. Final leg is they had previously parked drones along their expected commute routes for just such an occasion and..

edit: see interesting hypothetical future war series on YT, specifically this bit.. https://youtu.be/drr7mmibt9E?t=157