Log trucks can, when coming off a dirt road onto a public paved road (especially clay roads), can track dirt onto the road. Dirt, rocks and bark on the road can be a safety hazard to the general driving public. Where a problem exists the truck driver can either be forced to clean the tires prior to entering the public road, or the logger can use a road sweeper to periodically clean the road. It is typically mounted on the back of a small agricultural tractor and driven by the PTO.