But the biggest challenge was what to do with all those tires. Ford has found a way to re-use some of the rubber from the 4 million tires it has collected so far.
To reclaim the rubber, the tires are frozen to 180 degrees below zero Fahrenheit. When the tires shatter, the metal belts and fibers can be removed.
The process yields about 14 pounds of rubber from each tire, which Ford has used to re-pave an experimental section of highway in Arizona and high school parking lots in Detroit.