Bioturf Roads

We should genetically engineer a grass that is physically tough (like kevlar or spider silk); quickly grows to a certain height but slowly thereafter; able to withstand bright sunlight, deep shade, boggy swamps, rocky deserts, and temperature extremes; eats asphalt for lunch, sucks up carbon monoxide and carbon dioxide like a vacuum cleaner, and fixes nitrogen in the soil. Oh, and is easy to control (perhaps it is sterile and/or requires a particular element or compound to grow, like borax).

With such a bioturf (biological turf, as opposed to astroturf) we could replace the millions of miles of asphalt used on roads, highways, and parking lots with something a bit easier on the eyes, on the nose, and on the feet (barefoot jogging would be a lot of fun). Roads could soak up auto emissions and smog before it had a chance to travel very far, and they would be self-healing. We could even modify the grass to soak up energy in the summer and release it so the road stays just above freezing in the winter -- no more black ice or snow plows.