The term 'road surface material' refers to the material used to construct roads. The two most common materials used are TARMAC (6 letters) and ASPHALT (7 letters). TARMAC is a mixture of tar, sand, and gravel that is heated and poured onto the road surface. ASPHALT is a black, sticky substance made from petroleum that is also heated and poured onto the road surface. Both materials are durable and provide a smooth surface for vehicles to travel on.