For new or reconstructed pavements, the seal coat can be placed on a crushed stone or chemically treated base to provide a roadway with the least expensive permanent type of bituminous surface. Seal coats seal and protect the base and provide strength at the road surface so that the base can resist the abrasive and disruptive forces of traffic. Often these surfaces are placed in multiple treatments of two or three placements of successively smaller rock to enhance durability and reduce tire noise. A prepared road base structure that is to be surfaced using the seal coat concept should always be primed first. The asphalt in the prime should be compatible with the binder used to create the seal coat. Seal coats have been used successfully on both low- and high-traffic volume roadways, but tend to be more successful on low-volume roadways, especially low-volume truck traffic. Use of hot PG, polymer-modified, or asphalt rubber binders with larger grade rock (Grade 2 or 3) can improve the performance of seal coats under higher truck traffic conditions. The use of seal coats in urban areas where accelerating/decelerating traffic and turning movements frequently occur should be approached with caution. Binder application rates vary in accordance with the type/size of the treatment rock being placed, type of binder used, the level of traffic, and the condition/texture of the existing surface. See the for guidelines and methodologies for design of binder and aggregate application rates.