Review of existing system s

There are many asset m anagem ent systems available in the m arket, covering the main infrastructure types of road, rail, aviation and utilities, all with the common aim of providing support for decision making. Some systems deal with only one asset type (e.g. H D M -410 for road pavements) while others can be used across multiple asset types (e.g. dTIMs11 whose use has included road pavements, bridges, w ater and safety systems).

The following review aims to assess systems currently available on the m arket in order to understand:

• W hat system is state-of-the-art?

• W hat functionality is commonly employed within the models?

• Are there any gaps in what the models currently deliver?

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The main focus of systems and literature reviewed was from the UK, Europe, United States, Australia and New Zealand. With the fairly rapid pace at which new system versions are developed and the range and scope of what the systems cover, an all- inclusive review was impractical and certainly not within the scope of this thesis.

The assessments of each system can be seen in Appendix A, which contains a general overview of each tool and a table of the functionality of each reviewed model (see Table A - l) .

The criteria used to assess the models were:

• Infrastructure type;

• Platform and interface;

• Location referencing; and

• Analysis features.

This information was used in part to later define the specification for a pavement cost model whilst also understanding if (and how) any models currently include 'value' parameters.

2 .9 .1 Comm on fu n c tio n a lity

The review of systems showed that there are generally two categories of systems available on the m arket:

• General application systems: These systems represent w hat are commonly called

'off-the-shelf' solutions. These are marketed widely but they often require significant calibration if they want to be fully customised for local conditions; or

• Bespoke application systems: These systems are individually built around an

organisation's needs and their data. Condition relationships tend to be fully customised to use locally collected survey parameters and data. One of the

downsides of th at is that the customised rules and algorithms are less easily transferred to other networks an d /o r systems.

The degree to which the models fit into one of these categories is often ambiguous. To get the most benefit from an off-the-shelf solution there is significant calibration normally undertaken by the model provider or an independent consultant and the effort required (in tim e and resource) can often approach the effort required in the development of a bespoke system.

The level at which any model can be calibrated is influenced mostly by the quality and quantity of the tim e-series data available. In the case of the NRA there is a limited amount of historic data due to the survey frequency from previous contracts. This is due to improve under new contracts but it will take a number of survey cycles until the required quantity of data is available for robust data trending and calibration.

It was apparent th at the use of a database platform is fairly evenly spread between Oracle, SQL and MS Access. None of these platforms present a problem in the development of the model under this research although the main driver for the choice of platform is one th at is accepted by the NRA. The m ajority of systems make use of Geographical Inform ation Systems (G IS ) as the main interface, with Visual Basic, Java or web-based front ends also being used.

The most common level of operation of existing systems is at a network level (e.g. a road network is usually represented by a num ber of uniquely labelled sections which together form a network). There are some systems that operate at both the network and project level but what is unclear from the published information is if the same methodology (e.g. deterioration rules, treatm en t rules, scheme prioritisation) is used at both levels. This would be particularly relevant for any systems used to set or track a highway authority's progress against key performance measures. For exam ple, if the key performance measures are being set and/or tracked at a network level then the

in d iv id u al m a in te n a n c e s ch em es ( th a t in flu en c e th e o ve ra ll n e tw o rk m e a s u re ) should be m o d e lle d and d esig n ed using th e s a m e m e th o d o lo g y a t a p ro je c t le v e l.

O v e ra ll, it w as n o ted th a t s y s te m s in cluded one o r s e v e ra l o f th e ana ly sis o p tion s listed in Fig u re 2 -1 (w ith v a ry in g d e g re e s of p e rfo rm a n c e ).

C ondition p ro je c tio n W h o le -life costing R eporting

Model i

p rio ritis a tio n j

Risk based analysis

Perform ance m o n ito rin g

F ig u r e 2 - 1 : C o m m o n f e a t u r e s o f e x a m in e d s y s te m s

2 .9 .2 Unique aspects o f system s

T h e re w e re asp ects in th e re v ie w e d s ys te m s th a t w e re less c o m m o n across all of th e too ls. R a th e r c o u n te r-in tu itiv e ly , th e s e u n iq u e aspects w e re found m o re in th e g en e ral a p p lic a tio n s ys te m s (e .g . H D M -4 , C o n firm 12) ra th e r th a n th e b esp o ke a p p lic a tio n s . O ne reaso n fo r th is is p erh a p s b ecau se th e u n iq u e asp ec t adds a specific m a rk e tin g e d g e fo r

the product they are found in, hoping to set them apart from the competition of other general application models.

The unique aspects relevant within this research were:

• Asset valuation: The ability to determ ine the current value of an asset stock from

within a system; and

• Data integration: The ability to allow data from different geo-referenced frames to

be used together (e.g. referencing different data sources to a common fram e, but still allowing the user to work with the individual reference systems).

2 .9 .3 Id e n tifie d gaps

The review of models also highlighted gaps in the current systems on the m arket:

• There is limited inclusion of environmental issues within the modelling. HDM -4 has the option of including emissions, energy and noise but these inputs are far from common and most systems do not make reference to environmental criteria. In HDM-4 the vehicle emission pollutants are estimated as functions of the characteristics of the road, traffic levels, vehicle type and fuel consumption. Although these values are calculated they are not included in the economic evaluation (World Bank, 2 0 0 8 );

• The m ajority of current modelling frameworks require the user to already have

selected locations where maintenance is to be considered. That is, the system is used to select the best treatm en t for sites chosen by the user, rather than selecting its own sections for maintenance; and

• Often the condition of the maintenance sites is represented in a simplified way,

e.g. using single values for each of the defect parameters for the entire site. Using all the raw surveyed data would likely result in slow analysis tim es, but a more comprehensive representation of changing condition along a section would provide a closer representation of reality.

2 .9 .4 D evelo p in g a PMS

One clear option for developing a PMS is to draw upon elements or concepts of existing systems th at have already been developed. This not only saves on development tim e but it also allows the use of previously proven methods and techniques to be used rather than starting from scratch. One example of this is the PLATO Engine (Pavem ent Life­ cycle Analysis and Treatm ent Optimisation) which incorporates the Road User Effects models from HDM -4, and Road Deterioration and Works Effects models, originally from HDM -4 (but significantly altered to suit modern vehicles (Roberts et al., 2 0 0 3 )).

Two European projects looked at methodologies to generate a more integrated PMS for roads. RIMES (Road Infrastructure Maintenance Evaluation System) aimed to develop a fram ework for modelling road pavem ent performance and generate a common standard across Europe (Kokkalis et al., 2 0 0 2 ). The ultimate aim of the project was to develop a fram ework for a life-cycle cost model that could assess alternative maintenance strategies for both pavements and structures. The fram ework for a project level tool included road user costs (vehicle operating costs, journey tim e and accident costs) along with the costs of maintenance, discounting all costs throughout the analysis period in order to compare the life-cycle cost for maintenance alternatives. At a network level, it was suggested th at a probabilistic approach would form the pavem ent deterioration elem ent in order to find an optimal solution for the condition distribution. The different approaches could be used either to investigate policy impacts (network level) or to develop a maintenance programme (project level).

The PAV-ECO project undertaken at the same tim e, had the aim of developing economic models th at could be used by highway authorities across Europe within already existing pavem ent m anagem ent systems (Ertman Larsen et al., 2 0 0 1 ). A fram ework was developed that allowed for the life-cycle costs from competing maintenance strategies to be assessed, including both agency costs and road user costs. The project demonstrated how funds could be assessed against this type of model and distributed to different parts of the network using the more long-term costs and benefits rather than basing budgets

on historical trends. It was hoped th at the implementation of the findings from this research would be disseminated by both high authorities and consultants. However, the complexity still surrounding these topics is demonstrated by the remaining lack of standardisation in modelling road pavements. Although it could be argued th a t the fram ework for many models is broadly consistent, the varied im plementation of those frameworks by different highway authorities and private organisations results in very varied models and assumption.

2 .9 .5 S u m m a ry

The vast range of existing tools and the criteria used to assess them highlights the differences that exist across the available software (see Table A - l ) . I t also highlights the core elements th at are found between them , emphasising the base functionality that would be expected in most models and apart from risk-based analysis, this closely matched an outline of the functionality planned in the initial whole-life cost model (e.g. condition projection, whole-life costing, prioritisation).

However, despite the range of tools and the research undertaken into them there were still gaps that were apparent from this review. One of those in particular, the lack of inclusion of environmental parameters, aligns closely with this specific research. This gap however could also be indicative of challenges with incorporating the environm ent into road pavement tools; for exam ple, the lack of enthusiasm from the industry to model and use the data. This was a point that was noted for further exploration in the planned consultations with experts because it could influence the level of acceptance in any outputs.

2.10

Summary

Modelling road pavements is a well-documented field and has led to numerous systems being used by road agencies worldwide. The systems store a vast array of data for use in modelling and the algorithms used (e.g. defect relationships) can vary from simple linear

relationships to complex, m ulti-variable relationships. The interactions and relationships between the data is a key elem ent in developing a robust model.

W hole-life costing is a fundamental process in being able to identify an optimum intervention over a complete analysis period. In comparing whole-life cost approaches for different pavem ent analysis tools there is a common agreem ent of the costs th at are included in the economic appraisals (works costs and delay costs). However, road agency objectives change and the current position centres on giving consideration to w hat best meets the needs of all those involved not ju st what is the lowest cost.

To m eet the changing objectives faced by road agencies the principle of whole-life costing needs to be expanded to include assessment of wider stakeholder needs. This would mean the prioritisation of maintenance being made on a whole-life value basis that includes the consideration of externalities within the central appraisal and prioritisation of maintenance schemes.

Chapter 3

Externalities

As stated at the beginning of the previous chapter, the first research objective involves incorporating externalities in pavem ent maintenance assessments to take account of their impact in developing maintenance programmes. In order to develop modelling methodologies for the externalities of carbon and noise it was im portant to develop an understanding of externalities in road transport and how they can be measured. Therefore, this chapter reviews the available literature on externalities, with a specific focus on environmental externalities in road transport.

In the introduction, an externality was defined as resultant cost or benefit on an individual or an organisation from an action for which they were not originally responsible. There has been a growing recognition that externalities impose real costs on society and including externalities specific to road transport (e.g. health effects from noise) within appraisals has become an issue of growing importance (CE, 2 0 0 7 ). This has been due to an increase in understanding that internalising external effects in the appraisal process can give a better understanding of their total value. Value for money is defined by the OGC (OGC, 2 0 0 7 ) as

"...the optimum combination o f whole-life cost and quality to m e e t the user's requirem ents."