Kill. Me. Now.
Proponents of roundabouts in Japan argue that in the event of an earthquake disabling signals traffic can continue to flow. So lets go screw up out transport infrastructure, forever, for those very rare occasions that earthquakes take out our signals. Or we could forgo the much hated infrastructure and simply teach our motorists to give way to the right at uncontrolled intersections.
They also point out that roundabouts allow vehicles to flow smoothly when there is no traffic ahead, and that there is no need to come to a complete stop at an intersection if the road is clear. Roads in Japan are rarely clear, and roundabouts restrict the number of cars that can enter an intersection severely backing up traffic at busy times. Tokyo has nothing but busy times.
Traditionally cyclists and roundabouts have not mixed well, with numerous studies concluding that roundabouts place cyclists at greater risk than conventional intersections. Cyclists are at risk when entering the roundabout, they're at risk when cars enter the roundabout, and also risk being struck as cars exit the roundabout. In fact it is worse than that, with a recent study showing that a single lane roundabout creates an environment with 24 conflict points while drivers are expecting just 4, leaving them blind to 20 potential accident spots.
Lets hope this panel of "experts" do their homework thoroughly, considering bicycles and pedestrians, not just motor vehicles, in their roundabout strategy. They must keep in mind that bicycles are legally classified as light vehicles in Japan and required by law to travel on the road, therefore any infrastructure decisions that do not take into account the needs of cyclists are grossly negligent.
Currently the panel is simply compiling a report about reductions in accident rates and social changes that have occurred in countries that have introduced round abouts, therefore it still remains to be seen if roundabouts will start popping up around the country. Lets hope not.