Japan should take whatever measures necessary to ensure that no one else gets hurt because of the sinkhole. If that means closing down one of the main roads, then that's what they will have to do. People will understand that the decision was made for their protection, and they will take an alternative route.
In my opinion, the road over the sinkhole should remain closed as long as there is any reasonable doubt that it could threaten anyone's health or safety. The inconvenience caused by having to reroute traffic is not enough to outweigh the risk of valuable lives being lost. The government did the right thing.
Yes, Japan should close the road over the giant sinkhole until assurances can be given that the sinkhole will not reopen. While commerce may suffer for a short amount of time, preserving the safety of the public should be the most important task for the Japanese government. Assuring that the road is safe is a small price to ask if lives are on the line.
Yes, the rest of the world's countries should follow Canada's ban on microbeads. This is a serious public safety issue and should not be taken lightly. A serious investigation into the cause of the sinkhole and the stability of the ground both in that exact location and areas around it is absolutely necessary.