To environmentalists who believe that the technology could be harmful because of toxic fumes from plastic residue, Dr Vasudevan points out that the plastic used is softened at 170C. “Plastic decomposes to release toxic fumes only if it is heated at temperatures above 270C (518F). So there is no question of toxic gases being released,” he says. Since plastic coats the stone and interacts with the hot bitumen, it’s properties change and it doesn’t break down when exposed to light and heat.
Seems like it would break down less than a regular tar-only road and last longer to boot.