Just off the map sheet to the north is the intersection of Route 1036 and Route 101. Traffic flowed south from Vinh via Route 101 and trucks headed for Laos took Route 1036 south. Entrance to Ban Raving Pass
This route into Laos was not used early in the war because U.S. Air Force bombing in southern North Vietnam (between the 17th and 20th Parallels) was heavy and the coastal lowlands offered little in the way of concealment for long truck convoys. However, when President Lyndon Johnson announced a total halt to the bombing of North Vietnam it had an unintended consequence for both the Americans and the North Vietnamese.
Since there was no bombing in North Vietnam, trucks and trains headed south from Hanoi and Haiphong could benefit from the better road and rail networks in North Vietnam as opposed to the rougher roads in Laos. Also, the distance was a lot shorter and less fuel was needed since the trucks did not have to climb as many hills.
The other impetus for the North Vietnamese was the fact that aircraft which had been bombing in Route Packs 2 through 6 were now available to bomb in Route Pack 1, since there was never a bombing halt in Laos (remember, both the North Vietnamese and the U.S. government denied a presence in Laos). So NVA traffic which proceeded down the Mu Ghia and Ban Karai Passes and south through Laos would be subject to attack by even more aircraft than before.
The North Vietnamese solution was to shift traffic headed for Laos to the Ban Raving pass on Route 1036. The problem was that halfway through the pass, route 1036 went from a two lane all-weather gravel road to a footpath. Construction on the road was halted in the late 1950s when the road reached a section which was too steep for the equipment the NVA had available at the time.
With their new influx of construction equipment from the Soviets in the mid-1960s however, it would suddenly be feasible to punch through the steep passes and complete the road all the way to Route 92 in Laos, not far from Tchepone and NVA Base Area 604 below the DMZ. This was a win-win for the NVA. It meant convoys could stay in the sanctuary of North Vietnam for much more of their trip south, and emerge into Laos much closer to their destinations, limiting their exposure to interdiction by the U.S. Air Force.
The Misty FACs eventually caught on to this strategy and air strikes were directed at Ban Raving Pass, but by then it was too late. Lyndon Johnson threw away any chance of victory in South Vietnam with his unilateral bombing halt in 1968.