This why here in Finland a lot of rural roads are being converted back to dirt. Basically keep the asphalt for as long as it can be with cheap repairs and once it needs to be redone just rip it off and put some gravel. Maintenance for these is cheap using existing infrastructure (trucks and loaders that the municipality already owns for winter/snow). Basically every spring just relevel it with a blade attached to a truck and add a bit of gravel.
Is tire wear => microplastics an environmental concern that has been quantified? This is a new concept to me and I have no idea how to weigh the potential costs of this factor.
You could just put the 3 words without the => between them into some search thing and get many hits. It's significant.
Maybe less so if country roads with low traffic as poster downwards suggested. But tyres are soft, so it seems only logically they are abraded faster by gravel which is harder and has sharper edges, than a more flat surface.
