A high-quality transportation system is a necessity in a modern economy. The road network is a common, and perhaps the most significant, component of a transportation system and an essential part of all modern economies. Road systems are developed to enable the safe movement of passenger vehicles and freight at reasonable speed. Meeting this objective is essential for an efficient economy. A functional road network is not only an important part of the transportation system but also an expensive investment. Good policy requires that infrastructure investment should provide a return on the investment. This investment warrants judicious management to ensure the infrastructure is maintained in a cost-effective manner. This study proposed and developed the concept of a new Sustainability Index for Roads (SIR) using the three pillars of sustainability namely, economic, social and environmental. The reasons for implementing an index solely for roads are: to minimise the cost of road rehabilitation (has a high ongoing cost) (economic); involve the community (has little knowledge to make informed decisions) (social); and, to reduce the environmental impact of annual road rehabilitation programs across Australia (environmental). This SIR provides an alternative approach to determine the optimal future target Pavement Condition Index (PCI) for a local government authority (LGA). The newly developed SIR includes a community consultation option to make a more informed decision when choosing a future target PCI. This decision involves balancing the community’s expectations (social pillar) regarding the annual road rehabilitation budget (economic pillar) with particular reference to the return on investment (ROI) for their annual road budget and both the financial and environmental costs (environmental pillar) of the different pavement design options for the rehabilitation of roads. This study also produced a new tool for estimating the Return on Investment for the local government that provided their data for this study, for the rehabilitation of their road network. The study also provided a transparent low-cost method, to engage community representatives to consider what the community was willing to fund, using the ROI as above. The study also investigated the two most common road rehabilitation design types that incur different environmental impacts, from the local government works program. The study demonstrated that there is a difference in the environmental harm caused by the different road rehabilitation designs and that this difference can be shown in terms of costs to be incurred. The SIR developed in this study equips the community with the knowledge to make informed decisions about the pavement condition and environmental harm they are willing to fund, paving the way for better road management by the relevant authority. The SIR is the community’s chosen Pavement Condition Index (PCI) after consideration the new ROI curve (Future PCI Versus annual Budgets) relative to the achieved PCI is an alternative road network specific measure of asset sustainability to the current Queensland ASR.