It seems odd that ‘Construction Area’ signs are needed to indicate a construction area. Theoretically, it must be sufficiently visible to all. However, this is not always the case. It can happen that one gets lost on a construction field in the night without paying attention. If the site on which the work is being done is usually free, it is important to warn those who use it or cross it in order to avoid accidents.
Construction area signs can be used to indicate the road that heavy transport can take to go to the site, and they can warn people who have nothing to do on the site to avoid going there. They may also indicate the type of protective clothing required on the job site.