True for most permanent road signs.

But look out for the temporary signs that road crews put up - Especially the ones that are covered with pictures of pretty flowers and positioned just before a blind curve.

The first time I came across this kind of sign, I assumed that someone was selling flowers up ahead. Although I could read Japanese at the time, I was a slow reader and a fast driver. I didn't have time to absorb the message "We apologize for the inconvenience. There are roadworks 50m ahead". I discovered my error very soon after I turned the corner...