Most vehicles don't have hundreds of people onboard or the mass and kinetic energy to kill hundreds (or thousands, in case it crashes into a skyscraper) more on the ground.
The closest you can get is a couple dozens on a bus, and we regularly have issues with tired/stressed drivers there and catastrophic incidents - but unlike airspace, next to zero enforcement of protection rules :/
True, but all vehicles operate on the same road system that does have such vehicles and the kinetic energy of any vehicle at highway speeds is most impressive.
The closest you can get is a couple dozens on a bus, and we regularly have issues with tired/stressed drivers there and catastrophic incidents - but unlike airspace, next to zero enforcement of protection rules :/