After one year, transport activities on the road temporarily halted when the U.S. discovered and swept the area.
Vietnam's northern troops switched to the western flank, opening routes through Lao territory to avoid detection. In 1961, the support route was extended nearly 100 km from Quang Tri to Laos' Muong Phalan. It was made usable by horses, elephants, carts, and some motor vehicles, all of which carried supplies, weapons and other equipment through the mountainous jungle in support of the anti-colonial struggle.
The Truong Son Road transportation network consisted of three parallel systems by 1964, including liaison roads, porterage routes, and motorized transport routes.
In the picture, from left to right, are troops navigating the precarious paths of Truong Son at the end of 1966, liaisons crossing a 1,500 m high peak at La Hap, and sappers on another peak.