sentences:  It does not connect with the South American road network due to the Darién Gap.Some roads are seasonal, such as ice roads that cover frozen bodies of water, winter roads which cross otherwise impassable wetlands only in cold weather, and unpaved mountain roads that turn to mud in the spring.The road network does not reach all settlements, and some remote arctic and subarctic communities are only accessible by seasonal road, open land, sea, or air transport.