In this chapter, the following terms have the meanings indicated. Terms Defined. “Bulk” means a total load which is in a mass, not packaged in separate units, and which cannot be counted. Containerized cargo is not considered to be bulk. “Feed” means food for animals or birds. Loose Material. “Loose material” means feed, dirt, sand, wood chips, stone, gravel, aggregate, solid waste, ready-mix concrete, or other similar material that can blow, fall, or spill from a vehicle as a result of movement or of exposure to air, wind, or weather. “Loose material” does not include agricultural products in their natural state, liquid loads, or concrete blocks. “Self-unloading by gravity or mechanical means” means that once the unloading process is started, gravity or a mechanism which is an integral part of the vehicle takes over the unloading process.