Bridge-in-a-backpack? Say what? Well, the University of Maine is researching an "innovative inflatable composite-concrete arch bridge," which it cleverly describes as bridge in a backpack. The technology is more than a decade in the making from the university's Advanced Structures and Composites Center. Researchers there say that the technology can reduce construction time and costs, potentially double the life span of bridges, reduce maintenance costs and significantly reduce the carbon footprint of bridge construction.