The toxic materials and other wastes that drip or are expelled from motor vehicles. Stephen Goldsmith coined the term in 2001. He was planning director for Salt Lake City, Utah, working with the mayor to stop a proposed inter-city highway that would bring tens of thousands more cars into the city. ‘The impacts to water and air quality would require the city to process the autoguano, some of which (like rubber dust) is not manageable,’ Goldsmith recalls. ‘The word creates an immediate image for people who otherwise don’t see the beast for what it is. “Autoguano” is particularly illustrative when I speak to people about all the stuff the car brings into their attached garages, as though it were a filthy pet invited into the house. Since most attached garages in the US connect directly to the kitchen, an awareness of the health risks is easy for people to digest when the word is introduced.’