This is what the bikepath is like during the Tour. Not quite as peaceful, but not as dangerous as you might think: cyclists in Japan are very considerate about pointing out obstructions to the riders behind.

The bikepath goes back and forth, sometimes on the ocean side and sometimes on the mountain side of the expressway. Signs point out when the path is going to go through a short tunnel. According to this sign, this is the "Noto Beach Bikepath."