For all motorists, but perhaps the Ferrari-collecting rocker Rod Stewart in particular, it will be music to the ears: researchers have developed a road surface that heals when it cracks, preventing potholes without a need for human intervention.The international team devised a self-healing bitumen that mends cracks as they form by fusing the asphalt back together. In laboratory tests, pieces of the material repaired small fractures within an hour of them first appearing.“When you close the crack...