Cross-section Plan Measure of thickness : Based on dense layer 1)OVERLAY after cutting -Connect by drilling a hole at the side of rain water pipe -Secure lower waterproof layer (Asphalt/Concrete) at the drainage layer. -In case of cutting sloping area and others : After giving sloping treatment ( above 30 degrees) connect cross joint to side holes (rain water pipe) <Drainage Works on the side> 2)OVERLAY(no cutting) : Covering -Lay down pavement at 5-10cm inside the road from the outerline of impermeable road shoulders -Natural drainage using shoulders -Secure waterproof layer(Asphalt/Concrete) at the bottom of permeable layer. <Drain Works Of Road Shoulder> 1) Standard construction thickness of outer layer of drain asphalt is shown on the next table. Essential factors shall be fully examined before laying down on the base layer. Standard construction thickness and Maximum aggregate diameter Standard construction thickness maximum diameter of the aggregate 4§¯ 5§¯ 13§® 19§® 2) Basically, when drain asphalt is used on the bridge, waterproof layer should be built on the upper plate. Also, full examination of the structure of drainage layer is necessary. 3) Full examination is necessary when adjusting traffic safety equipment, based on the changes of water circulation in drainage structure. When drain asphalt is used for median strip or road shoulder, the height of road surface should be taken into account