Someday, someone can look back through this thread and see the development of this crisis from "there'll be no war in Ukraine" to "OMG! they just nuked Keeev!
I'm not sure a roadblock will be much use against a fully armed T-70 tank but that convoy is ripe for an ambush - if the Ukrainians had the men and materiel to pull off such a manoeuvre. With complete control of the sky Russian jets can let rip as Stage Two of this 'special operation' gets underway and Putin decides it's no good pussyfooting about unless they want to lose any more momentum. He must decide on this next phase very carefully, balancing the collatoral damage of civilians and non-military targets against achieving tactical and strategic objectives quickly.
I expect the Red Army will revert to type and blast away at anything in their way, shoot anything that moves, and march on regardless of casualties.
Putin cannot afford to lose face in the eyes of the world and has to get this done quickly. If they haven't captured Keeeev by mid-march serious questions will be asked at the highest level, and holidays in Siberia will be arranged.
Maybe. I'm just one of many armchair generals watching on from afar and has the luxury of making half-arsed assessments without any risk but ...
The mere suggestion of using Tactical nukes has made Western observers very nervous and who can say Putin won't become desperate enough to go that far? This is becoming a zero-sum game.