Every year, billions of vehicles worldwide shed an estimated 6 million tons of tire fragments. These tiny flakes of plastic, generated by the wear and tear of normal driving, eventually accumulate in the soil, in rivers and lakes, and even in our food. Researchers in South China recently found tire-derived chemicals in most human urine samples.
Material sciences is a difficult field. People spend years researching one small area just to shelve their research as not viable, too cost prohibitive, or impractical for large scale manufacturing.
I haven’t seen any research into durable biodegradable materials that could hold the weight of vehicles unfortunately, so I think investment will be hard to come by. Though I don’t disagree with the premise that something that can degrade over time, but also not harm the environment would be an ideal solution to the problem. I imagine if such a thing were created it would be able to be applied to many other industries, not just transportation.