It would possibly a great energy saver to roof our roads with a cheap but strong material which cuts off the sunlight during the hot summer months. We would save on considerable need for air conditioning from cars as these would get significantly less hot while on the roads. Besides the tarmac would heat up less and therefore serve a longer lifetime (we all know how guie it becomes in the scorching noon sun, flattening it out and thus removing its water draining and grip properties). Third it would mean less fuel burnt on the roads and therefore cleaner air for all of us. A wild idea, but could it work?