steamroller

A steam-driven machine equipped with a heavy roller for smoothing road surfaces.

A similar machine with an internal-combustion engine.

A ruthless or irresistible force or power.

To smooth or level (a road) with a steamroller.

To overwhelm or suppress ruthlessly; crush.

To move or proceed with overwhelming or crushing force.

a steam–powered heavy road roller

Any heavy road roller

any seemingly irresistible force