Tangent: I've long wondered when we'd see invention of drop-in roads - transportable segments of self-leveling roadways, robust enough for heavy use & a substan

Tangent: I've long wondered when we'd see invention of drop-in roads - transportable segments of self-leveling roadways, robust enough for heavy use & a substantial lifespan yet easily disconnected & replaced (unlike current stubbornly permanent structures). In that context, I'm interested to the answer to your question.