Rollers are used to compact a material to a pre-specified density. The work may only account for a small fraction of the total project cost, but if compactors fail to meet specifications, an entire job can back up and slow down. It means big money costs. Vibration dampened platforms, swivel seats for good visibility, logically sorted controls, Roll Over Protective Structures (ROPS) and more all contribute to operator comfort and safety. Equipment such as compaction meters and computerised analysis equipment are available to help contractors with their quality assurance work.