Recycling plastic waste into other materials is a great idea, but use as a surface for travel may not be ideal.  [In India, there have already been places that have successfully integrated plastic into their roads.](https://www.theguardian.com/sustainable-business/2016/jun/30/plastic-road-india-tar-plastic-transport-environment-pollution-waste)  The other side of this is that as these roads wear, the plastic wears into tiny particles that then enter the areas surrounding the roadway, including streams and rivers.  And while we're not yet 100% sure how microplastics impact the ecosystem, unless it's somehow "not negatively at all!" we're probably better off looking for other ways to use old plastic.