Why did they close the highway?

The highways through Tokyo are famous for stationary traffic but in reality are usually free flowing and open. One night recently, coming back from Yokohama, the police closed the road and set a blockade just before Haneda Airport. When I asked he explained it was for "security reasons" but wouldn't say any more. Now, even for the Emperor they use a rolling blockade rather than a fixed one. The next night One Direction played Tokyo. Coincidence?

This blog is to help people understand Japan and make their lives simpler here. If you have any questions please feel free to ask in the comments below.