To differentiate between operational areas and traffic areas clearly so that they do not mingle with traffic, work, and materials used in construction, as well as the cause of the accident.
The separation between the operation and the traffic is clearly not to be confused with the traffic and the construction materials used, the cause of the accident.
Discrimination between area and area operation area clearly to prevent traffic การจราจรปะปน with those who work materials and equipment used construction as the cause of the accident.