A salient feature of the situation in South Vietnam, during the period covered by this report, has been the degree of access of governmental authority and normal commerce to large segments of the population and the countryside. In early 1968 both the railroads and the highway and secondary road systems had been heavily interdicted. For all practical purposes movement was limited to those routes required for continuing military traffic and to travel by aircraft between population centers large enough to support fixed wing airfields. Although military forces were able to enter virtually any area at will, commerce was stagnant and regular governmental services were limited to province capitals and other population centers. This situation provided fertile areas for VC attack on residual governmental authority and for assumption of control by the VC infrastructure. As US engineer effort has shifted from the development of bases and fixed facilities to the opening, rehabilitation and upgrading of the major highway system, ARVN and other GVN construction agencies have tended to follow suit, opening railways and secondary feeder roads in concert with the highway program. The expansion in the means for access to the countryside has been a vital ingredient in the acceleration of the pacification program and in the revitalization of intra-Vietnam commerce, agriculture and industry. In the long run, this may be the most important US Engineer contribution--second only to the construction of the facilities through which forces were deployed into Vietnam--to the success of the US undertaking in Vietnam.