ABSTRACT
Infrastructure network expansion was initiated after World War II. Highway agencies focused on the construction of infrastructure networks. Road and rail networks were developed to provide mobility and effi ciency in different modes of transportation to users. The infrastructure network expansion slowed down after the late 1970s because of shifts in focus from expansion to preservation. Figure 24.1 captures the historical timeline from infrastructure network expansion to the present. Shifts in federal, state, and local policies relative to infrastructure management and expansion, budgeting decisions, and staff resource allocations over the last twenty to thirty years have impacted transportation investment decisions and are likely to play a key role in the future. Highway agencies continue to face tough challenges in simultaneously expanding and maintaining the infrastructure network. To assist, different technologies have been incorporated to maintain the infrastructure network to prevent catastrophic failure while providing a safe network for users. Among the technologies introduced were the concepts of single-asset-type management systems such as the pavement management system and bridge management system in the late 1970s to 1990s as shown in Figure 24.1.
