Polymer-modified binders are mainly used in proprietary ATS systems which are typically laid 25 mm thick. These materials deliver high levels of traffic noise reduction whilst retaining high surface texture under heavy traffic loading for maintained skidding resistance. They also offer less disruption to the road user during installation, and when specified as an asphalt overlay there is less need to adjust kerb levels. Also bridge height clearances are protected.

Polymers reinforce bitumen by improving cohesive strength, making it more resilient and tougher. Thin asphalt surfacings are relatively new to the UK following their introduction in the early to mid-1990s. However, today, all of the major asphalt suppliers are able to supply such materials in accordance with clause 942 for thin surface course systems in the specification for highway works (a.14).

Before ATS were introduced into the UK, the premier asphalt surfacing material was HRA. Whereas ATS rely on having a high stone content bound together with a rich bitumen/filler mastic matrix, HRA works in a different way by having a relatively low stone content, relying on a stiff mastic made of bitumen and filler in combination with a high stability sand to provide the necessary stiffness and resistance to rutting by traffic. Polymers have been used, and are still occasionally used, in HRA mixtures in accordance with clause 943 of the specification for highway works (Performance Related Design Mix). This was introduced after the hot summers of the mid-1990s caused a number of rutting problems across the road network.