The first and the most surprising impression I got in Japan is about traffic. At the crossroad without traffic light, the cars will always stop far away and let the pedestrians go first; when there is traffic light, very few people travel against the signal color.
These are totally different from what I see and experience in China. While spending extremely large amount of money on inter-city railways, the authorities have nothing to do about the traffic issue in the ever-growing large cities. The width of the road has zero impact on how fast we can go, but just determines how many cars are trapped by traffic jam per unit length.