Although plastic particles in the air are increasingly coming into focus, knowledge about their distribution and effects is still limited. Chemical analyses from Leipzig now provide details from Germany for the first time: Around 4% of the particulate matter consists of plastic. Around two-thirds of this comes from tire abrasion.
Metal would wear out too fast on asphalt/concrete though. What if we used metal tyres on metal roads? Less friction, less abrasion! It’d be expensive though to replace the whole road. Maybe just a pair of strips the same width as the tyre spacing. Cars could even connect to each other to reduce aerodynamic drag… Nah, would never work