Developing a Whole-Life Value Model for the Irish National Road Network

Buckland, Thomas (2015). Developing a Whole-Life Value Model for the Irish National Road Network. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000efcd

Abstract

Planning of road maintenance helps to spend available budgets efficiently and aims to keep the network in a safe and useable condition for road users. Road pavement maintenance models have traditionally excluded externalities as part of quantitative assessments of maintenance options. However, road maintenance affects wider society and therefore any maintenance decisions should integrate externalities into the decisions and tools that are used to generate maintenance programmes. This thesis investigates how externalities of carbon and noise emissions from maintenance can be included in a pavement maintenance model and the associated impacts on developing a maintenance programme.

Pavement maintenance models were studied and it showed that there is a general omission of externalities within the core of the models. A review of externalities (with an emphasis on environmental externalities) demonstrated that road authorities do have policies to take account of externalities but often in a qualitative assessment and often only at a project level, not at a strategic level.

This research developed a whole-life cost model into which novel methodologies for modelling carbon and noise were included, with the methodologies developed so that they can be used in other pavement management systems. The result was a model that took account of a wider range of value parameters as part of the economic analysis. Two in-depth case studies were completed to investigate the impact that the methodologies had on a road network. Using current government prices for carbon and noise, noise had a significantly greater impact on the resulting maintenance programme. Sensitivity analysis showed that the resulting maintenance programmes were a lot less sensitive to changes in the price of carbon, although both parameters did lead to changes in the resulting maintenance programme, especially when specific environmentally focused maintenance options were included as treatments.