9
 propedly manned maintenance facilities, and the variety of truc, imports has
 resulted in a flect of over 30 models from at least seven different countrics. POL.
 imports into North Vietnam during the first half of 1967 have been at record
 levels, and we have had no evidence of any serious POL shortages affecting
 the movement of supplies to South Vietnam.

17. Waterways. The coastal and inland waterway system in North Vietnam
 provides a useful supplement to the road and rail system and has been used
 extensively, particularly since the start of the US bombing program. Although
 the mining of some North Vietnamese waterways has reduced the movement of
 large craft, small boat traffic ocntinues. Increasing imports of barges and barge
 sections into North Vietnam and a program of waterway improvement indicate
 that the Communists intend to exploit further the potentialities of these water
 routes. In Laos, there has been increased use of small pirogues and motorboats
 on rivers over the last year. The use of these waterways will probalby
 continue to increase.

18. Rail. The North Vietnamese also use the rail line south of Hanoi for
 movement of supplies into MR-4. Despite repeated US air attacks, the North
 Vietnamese have been able to construct bypasses and keep sections of the line
 serviceable from Hanoi to Vinh. South of Vinh the rail line is not operable for
 regular rail equipment. The North Vietnamese can only use light gear, principally
 trucks with converted wheels, to transport supplies over the remaining
 rail segment in this area.

19. Impact of Air Attacks. Air attacks in North Vietnam, Laos, and the
 DMZ have destroyed trucks, railroad rolling stock, and watercraft, have damaged
 the highway and rail systems, and have restricted the movement of cargo and
 personnel particularly during daylight hours. They have created construction
 problems and delays, caused interruptions in the flow of men and supplies,
 caused a great loss of work-hours, and forced North Vietnam to tie up large
 numbers of people in air defense and in the repair of LOCs. Communist countermeasures
 in North Vietnam and Laos have included diversification of the
 means of transport to include greater use of inland waterways and porter trails,
 construction of alternate roads, and of multiple bypasses at important bridges.
 A number of truck parks an vehicle pulloffs for quick convoy dispersal have
 been built. These measures have increased the ability of the Communists to
 cope with the effects of air attacks, although at a considerable cost and effort.
 Units and personnel moving to South Vietnam have been forced to move under
 cover of darkness, slowing their movement and subjecting them to the rigors
 of the trail for longer periods.

20. Cambodia. The importance of Cambodia as a sanctury and a source of
 supply (principally rice) to the Communist war effort is substantial and growing.5
 Recently captured documents indicate that some Communist units in Tay Ninh
 5 For a more detailed discussion of this subject, see SNIE 57-67, "Significance of Cambodia
 to the Vietnamese Communist War Effort," dated 19 January 1967, SECRET. We believe
 the conclusions are still valid.


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 TS 186035