Roadway network as a degrading system: vulnerability and system level performance

Views of both researchers and practitioners towards transportation infrastructure performance have experienced notable changes in the past few years. Strategic level decision-makers are more interested in knowing the performance of roadways and systems as a whole rather than the performance of the asset level components. With interdependent and complex infrastructure, many researchers have attempted to study the vulnerability of infrastructure to disasters and catastrophes as an important system level performance measure. This paper reviews the literature, extends the discussion and proposes new directions on vulnerability and performance evaluation of roadways. This paper reviews how performance assessment in transportation infrastructure – and particularly roadway systems – has been addressed from asset level to a wider system level perspective. Infrastructure interdependencies and network science, as two necessary components of system level performance and vulnerability assessment, are discussed. The significant impact of the condition of the roadway system on its performance and vulnerability is explained and condition based approaches are proposed. Finally, the advantages of, and contributions derived from, using a condition based approach to vulnerability assessment with current management systems of roadway infrastructure are explained.