Life-cycle planning methodology for ancillary highway assets

Abstract

Central to the development of highway asset management plans is the creation of life-cycle plans for all highway assets. Understandably, significant effort has been focused to date on the condition and performance of the carriageway and structures stock, given their overall asset value. However, an understanding of current asset condition and future asset performance is lacking in most authorities for their ancillary highway assets, such as road markings or road lighting columns. A number of life-cycle planning tools are available to develop life-cycle plans, both deterministic and stochastic in nature. The challenge in including ancillary highway assets in a stochastic modelling process is the determination of the current condition of the assets, represented by a distribution of condition, and the modelling of deterioration, represented by a transition probability matrix. The methodology outlined in this paper allows for the current condition of the assets to be assessed either visually, through walked surveys or from video survey footage, or using data collection devices, where appropriate. The current condition of the assets is then translated into distributions of condition for onward use in the model. The asset lives were captured using expert engineering opinion and, through some simple assumptions, translated into transition probability matrices. A pilot study was undertaken on a London borough's principal road network, as a proof of concept, and road markings have been used throughout to demonstrate the methodology. In this pilot study, video survey footage was used to assess asset condition. Lessons learned and recommendations are included for other authorities wishing to follow a similar methodology.