Source: American Motor Vehicle Manufacturers Association
Source: American Motor Vehicle Manufacturers Association of the world (Table 36.1). The car also creates system-wide demands for greater roadway infrastructure and travel (Graedel and Allenby 1998).
One positive aspect to car use is the extent to which material recycling is being achieved. Recycling car components and materials is a large industry, with some 10 million scrap vehicles processed annually (AAMA 1993). In the disposal process, valuable components are first removed for either direct re-use or special disposal. The remaining hulks are usually shredded and metal pieces recovered. In Europe, there are some initiatives among motor vehicle manufacturers to take back old vehicles and recycle a large fraction of the vehicle mass, so even more of the vehicle may be re-used.
Non-metallic waste from the shredding operation (known as 'fluff) is generally not recycled (Isaacs and Gupta 1997). It is made up of plastics, fluids, dirt, rubber, fabric, glass and other materials, commonly referred to as the car shredder residue. While fluff is generally treated as a non-hazardous waste, potential troubles exist: California considers it a hazardous waste, while Rhode Island and Massachusetts require testing for hazardous content (Dvorak 1993). Automotive fuel tanks have been made from steel for many years, but plastic tanks have recently been introduced to save on vehicle weight (Joshi 1999). The advantages of molding complex shapes allows easier placement of the fuel tank in a vehicle. Complex geometries make the tank harder to drain at the end of life. Gasoline absorbed into the plastic that may be released in a drained tank creates problems for shredders. Plastic tanks with combustible mixtures are a hazard for shredding equipment.
Engine emissions from car use are subject to increasingly stringent regulation. There is growing interest in moving from 'end-of-the-pipe' treatment systems (such as catalytic converters) to alternative fuels and hybrid and/or electric cars. A difficulty with electric battery cars is the toxic materials in the batteries, especially over the life cycle of battery recycling, even if only traces are lost to the environment (Lave et al. 1995; McMichael and Hendrickson 1998).
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