Other than their functions as research centers and control posts, these substations are also gateways to the historic Salt Trail. It was, and still is, a trade route used by the villagers from the remote villages in the forest, accessible only by foot, to travel out to the towns. The 35.8km Salt Trail requires at least 3-4 days of jungle trekking, from Inobong to Malungung (Tikolod), or vice versa.