Did you realise that there were no round-abouts in Japan (at least, I have never seen any) ?

There are also very few tunnels inside Tokyo, compared to older cities like Paris or Brussels, where you spend more time in tunnels than outside if you decide to take a turn on the ring road. Streets are too narrow to cope with the high affluence. Tokyo has been kind of blessed to have the opportunity to redesign its street plan after the WWII ground destruction (I know, it's a double-edge compliment as it also lost most of its historical heritage, but earthquakes have helped before anyway).

As a consequence, bottlenecks are scarce, even during the peaks, also thanks to the effecient synchornisation of traffic lights. The idea is to canalise the traffic on the large straight 6-lane arteries or on high-speed elevated motorways, whilst secondary streets are left as empty and narrow backstreets (what make them for convenient for bicycles and pedestrians).

The city's roads are built in the sky. The kousokudouro (expressway) fly above your head and cast their shadows on the surrounding concrete buildings. In this respect, Tokyo shares a lot with other Asian capitals like Bangkok or Seoul - which have been quick to catch up with their Japanese counterpart.

I was also quite surprised by the absence of squares in Japanese cities. Every Western city has its famous gathering place : Trafalgar square or Leicester Square in London, Time Square in NY, all the "places" in Paris (Vendome, Opera, Bastille...), Alexander or Potzdamer Platz in Berlin, the inumerable plaza in every Italian city... Most European cities have a City Hall square, several "market square" (even if cafes have taken over the market) and maybe some other as well. You'll usually find a Plaza Mayor in Spain, a Groote Markt in the Netherlands and Flanders, a Rathaus Platz in Germany...
30-million-people Tokyo has very little "wasted space". I can hardly think of even a minor square (広場 hiroba). There is a kind of little one around a fountain in front of Shimbashi Station and the overcrowded Hachiko meeting point in Shibuya, but they are wouldn't even qualify as a square in a minor European town.

What we learn from this here is that Japanese people prefer sacrificing architectural beauty and traditional meeting squares (where disgruntled populace can also gather to demonstrate) to the efficency of elevated highway in the middle of glamorous department stores and historical temples and making sure that every bit of space is used profitably (as land cost so much there).