Maine's Department of Transportation plans to build six additional composite bridges during its 2010-2011 construction cycle. Harbor Technologies President Martin Grimnes recently described the potential market for composite bridges as "gargantuan." His company will build a composite bridge that will connect an island to the mainland. The span of a composite bridge is stronger and more durable than concrete and weighs about half as much, observers say. They also note that composite bridges are expected to last longer than traditional bridges and require less maintenance.