In Japan, the number of roundabouts is increasing year by year. Many Japanese people understand that roundabouts are suitable for Japan, where natural disasters such as earthquakes are relatively frequent, because they do not require traffic lights. I am a Japanese person who likes roundabouts.
as a southern european traveling now across cities and countryside in Japan by public transport only I am really shocked about the profesional and civic way of driving in this country since my point of view as a pedestrian. Roundabouts could only improve the traffic in Japan, but the learning curve and assimilation of the rules and new Yield signs should be done step by step. I have seen in France a redundant informative sign in every access to every roundabout wich states "you don't have priority of way". It is certanly expensive as I have only see that sign in France but I think it will work well in Japan. Side note : in 15 days of travel only noticed 3 times oh honking!!! AMAZING !!!
One problem to overcome is that the "give way" sign in Japan has been utilized for a "stop" (tomare). So, you'll have to teach the Japanese the proper "give way" (yuzure) sign, which will be unfamiliar to most.
Even as a pedestrian, I don't like the roads in Japan compared to the UK. It's also strange to me how drivers can turn left while pedestrians are crossing the road. If the prefectures introduced more roundabouts, mini-roundabouts and actuated signals, my experience could be so much better. And also, there would be fewer drivers driving through red lights, because they wouldn't need to wait as long at junctions.