Optimising local council's return on investment from annual pavement rehabilitation budgets through targeting of the average pavement condition index

A high quality transportation system is necessary in a modern economy, and a road network is a common and significant, component of the system. Road systems have two major objectives: to enable the movement of passenger vehicles and the movement of freight vehicles at reasonable speeds. An important part of the transportation system and an expensive investment, a functional road network must meet both objectives to maintain an efficient economy. In Australia, the Department of Infrastructure and Regional Development reported that, in 2011/12, the total road length was approximately 900,000 km, and the total road expenditure was approximately $19 billion. Good policy requires that infrastructure investments provide a return on investment, thus warranting judicious management to ensure that it is maintained in a cost effective manner. Recent studies in Queensland, Australia, have identified differences between financial and engineering professionals in their understanding of infrastructure depreciation, condition deterioration, and future funding needs. Furthermore, the Queensland Asset Sustainability Ratio (ASR) requires clearer definitions to ensure that infrastructure remains meaningful to all users. This study proposes a separate sustainability index for road pavements (SIR) unlike the ASR that combines all type of assets. The justification is our ability to assess road condition, the high value of road assets, relative value to other infrastructure, and advanced knowledge of deterioration relative to other infrastructure. The SIR involves community consultation to target an average pavement condition index (PCI). This study also provides an alternative method to determine the optimal target PCI for a local government authority (LGA) that balances community expectations and funding levels, with a particular focus on return on investment (ROI) for the annual road reseal and rehabilitation budget.