The roads on mountainous Central Shikoku are, in general, in good condition, but they can be winding and narrow. The north part of the road in Iya Valley is one of the more extreme. Sections of the zigzagging two-way road are so narrow that cars can't pass each other. When they meet, one has to reverse to a wider part. Roadside mirrors are placed at many bends, but alertness and low speed is still essential to omit collision. Thankfully, Japanese are known to be courteous drivers.
Another spectacular roadtrip is the section of route 439, which connects Iya Valley with Oboke Gorge through the Kyobashira Pass (1133 m). This road is not in good condition, but it can be made in a regular car.