A road roller is a heavy construction machine used to compact soil, gravel, asphalt, or other road-building materials. It has one or more large steel drums or rubber tyres at the front and/or rear that apply high pressure to the ground. Road rollers are commonly used in road construction, airport runways, and large building foundations to create a smooth, firm, and stable surface. The machine may be powered by a diesel engine and comes in different types such as smooth drum rollers, pneumatic rollers, and vibratory rollers.

Operation
When the engine is started, it powers the movement of the roller and, in some types, activates vibration in the steel drum. As the machine moves forward or backward, the heavy drum rolls over the loose material, applying weight and pressure that forces the particles closer together. In vibratory rollers, the drum also vibrates, increasing the compaction effect by reducing air spaces within the material. The operator repeatedly passes over the surface in overlapping paths until the area becomes level, dense, and properly compacted for construction use.