The Use of Road Management Systems for Optimal Road Asset Management

Transcription

1 The Use of Road Management Systems for Optimal Road Asset Management M I Pinard, G Rohde * and R Frank Roads Department Private Bag 0026 Gaborone Botswana Africon Botswana* Private Bag BR 144 Gaborone Botswana Abstract The management of any country s road transport system is a complex task which is often influenced by a variety of factors - technical, economic, social, and political - which all enter into the decision making process at various levels of the organisation. In such an environment, determination of optimal strategies requires the use of a rational systems approach to road asset management. This paper outlines a framework for undertaking road asset management which is based on the strategy adopted for the development of Road Management Systems (RMS) in the Southern Africa Development Community (SADC) region. Data and results from the Botswana RMS are then used to illustrate how such systems can be operated to facilitate the management of a country's road asset in an optimal manner. 1. INTRODUCTION 1.1 Background Road transport is an important sector of economic activity in any country and the road asset usually represents a substantial public investment in transport infrastructure. It is therefore essential that this vital national asset is managed efficiently and cost-effectively in support of national economic development. The task of managing a road system in an optimal manner is technically complex, particularly where there are competing demands for limited resources. However, this task can be greatly simplified by employing an appropriate systems engineering approach in combination with modern day management techniques. The objectives of this paper are to outline the systems engineering and management concepts underlying the development of Road Management Systems (RMS). Based on data and results from the Botswana Road Management System (BRMS), the paper also indicates the manner in which these systems can be operated to assist road managers in managing their road networks efficiently and cost-effectively by setting and achieving their policy objectives.

2 2. FRAMEWORK FOR ROAD MANAGEMENT 2.1 Road Management System Concepts Systems Engineering: In principle, a system may be defined as a group or combination of interrelated, interdependent or interacting elements forming a collective entity. When the system is externally stimulated a response will be obtained corresponding to the way in which the elements interact. Thus, three variables are associated with a system: exciter variables or external actions called inputs which affect the behaviour of the system response variables or external symptoms called outputs which describe the behaviour of the system, and intermediate variables called internal interactions which determine the relation, called the transfer function, between the input and output. Figure 1 shows schematically the setup of a system, identifying the elements and the associated variables. EXCITER VARIABLES INTERACTING ELEMENT 1 ELEMENT 1 RESPONSE VARIABLES ELEMENT 1 Figure 1: Variables and Elements of a System The AASHTO Road Test that was carried out in the 1960s is an example of an experimental approach to obtain a mathematical expression which describes the performance of a Road System. The equation [Log (DT) + Log R] [Log P. P) = [9.36 Log (SN + 1) (S-3) 0.68] relates the exciter variables DT (design traffic) and R (regional factor = climate) to the response variables P (serviceability = behaviour) through the interrelated elements SN (structural number) and S (subgrade support).

3 2.1.2 The Road as a System: The road is a functioning entity which can be analysed by applying a systems engineering approach. Figure 2 shows schematically a Road System in which the traffic and climate are the inputs, the deterioration symptoms are the outputs and the transfer function which represents the interaction between the various elements of the road structure. PAVEMENT CLIMATE TRAFFIC BASE SUBBASE SUBGRADE r T DRAINAGE Figure 2: The Road as a System Management Techniques and Systems: Management is the technique, science or practice of planning and controlling and involves knowledge of the entity to be operated. Modern management techniques require cost-effectiveness, economic efficiency in the use of scarce funds and selection of technical standards, and accountability of the management through performance measures and transparent accounting procedures, amongst other things. When applied to a functioning entity it means operating and steering to achieve the organisation s preestablished objectives. Procedures to quantify and evaluate the variables associated with any management action are basic tools which should enable objective judgement of the performance. However, judgements are made by persons as a result of which subjective attitudes, such as optimism or pessimism, may affect them. In order to remove subjectiveness from decision making, a set of procedures is required to collect, validate, store and retrieve data which, when processed statistically, will remove the element of personal bias by providing the information in an objective form such as an index. Furthermore, evaluation procedures based on weighting or other criteria can be applied to obtain a priority ranking. Finally, external constraints may have to be taken into account when decisions are to be made. The organised setup of these procedures, criteria and constraints is called a Management System. In its broadest sense, a Management System provides the necessary tools to enable the user to: Do the right thing at the right time in the right place and at the right cost

4 2.1.4 Road Management: Road management can be viewed as the entire management process employed by a road authority in order to provide and maintain a road network. It therefore includes a number of diverse activities including the assessment of current and future needs for maintenance, rehabilitation, upgrading and geometric improvements of the various elements of the road system under the road authority s jurisdiction. The road management task has become more difficult as the range and complexity of issues have increased with the size and economic importance of road systems. As a result, many road agencies have had to resort to the use of Road Management Systems in the management of their road networks. A Road Management System may be defined as a system which employs a set of formalised procedures used by managers to evaluate alternative strategies in a systematic and co-ordinated manner with the objective of providing, maintaining and managing a road system at minimum cost and maximum efficiency. The procedures are used by the several managers of the road network, with the aid of computerised facilities, to produce information and evaluate alternative strategies in order to optimise the efficiency of the provision of new facilities and the maintenance of existing facilities, improving facilities to required standards according to changing circumstances and demands and projecting the needs for new facilities, where and when needed. The design of a Road Management System (RMS) is based on the concepts of systems engineering and management techniques that have been described above (Sinha and Fwa, 1986). Conceptually, therefore, a RMS may be considered as encompassing a number of inter-related components which collectively integrate into a loosely structured system which allows full functional integration between the Information System and the Decision Support Systems (DSS) as illustrated conceptually in Figure 3. DSS DSS DSS DSS Information System DSS DSS = Decision Support System DSS DSS DSS Data Transfer Figure 3: Conceptual Framework of a Road Management System

5 As indicated in Figure 3, the RMS framework comprises two major components: an information system, which collects, organises and manages data and information; decision-support systems, which comprise applications modules to process data and provide the information on which decisions can be based and ultimately implemented. 2.2 Generic Structure of a Road Management System Basic Components: The basic component of a RMS may be categorised on a functional basis under the following headings: Base information function elements: e.g. - Network Information - Traffic Information - Accident Information Evaluation function elements: e.g. - Pavement Management System - Bridge Management System - Traffic Signs Management System Control function elements e.g. - Cost Management System - Plant & Equipment Management System Road charging function elements e.g. - Road Use Pricing System Execution function elements e.g. - Maintenance Management System Operational Levels and Requirements: RMSs are structured to serve planning and decision-making responsibilities at various management levels. In a comprehensive RMS, three distinct operational levels are catered for, namely: Level 1: Policy/Executive Level: Entails long-term strategic planning in order to determine the policy and resources required to fulfil the aims of the organisation, in this case to assess the cost of alternative policies and their effect on the level of service provided by the road network and to secure the resources for the most attractive policy. Level 2: Planning Level: Entails short to medium term tactical planning by which the actions and their timing are specified in accordance with the aims, policy and resources of the organisation. It relates to the identification of deficiencies in the network, the definition of the general type and relative urgency of projects to improve them and the scheduling of the projects in accordance with available resources. Level 3: Execution Level: Relates to the operational planning and design for each project which is often a compromise between economy and the expected level of service over an analysis period. Each level of planning can be viewed as a precedent setting for lower levels of planning. Strategic level planning will therefore have as its outcome, a set of policies

6 (or changes to policy) which provide a framework within which tactical planning can take place. Tactical planning, in turn, will constrain the options to be considered at the operational or design level. Thus, another way of viewing the process is one of successive optimisation whereby higher levels of planning (and associated decision making) provide the constraints for sub-system optimisation. The successful operation of a RMS requires that: - there is a common reference for all sub-systems - updating (data collection) procedures must be undertaken regularly - historical data must not be lost in the process of updating - security of the systems/data must be safeguarded - a minimum complement of staff is available to operate the system - training and updating of knowledge is undertaken on a systematic basis Capabilities of Road Management Systems: In principle, as a decisionmaking tool, a RMS is capable of providing decision support for a number of road management activities such as pavement management, bridge management, traffic signs management, etc, at all three levels of management, namely, policy/executive, planning and execution. In so doing, a RMS would include an ability to: determine the most appropriate funding level to meet a specified standard; plan network improvements according to budget constraints; determine the effects of deferring maintenance on upkeep and road users costs; determine the effects on users costs of raising/lowering the quality standards of road pavements; assure cost-effectiveness through prioritisation based on comparison of the costs and benefits of alternatives; Technically, a RMS should: select the most effective maintenance methods; predict future performance of pavements and evaluate costs/benefits of strategies; learn from past and present facts and figures and improve construction and maintenance techniques develop maintenance strategies; Administratively, a RMS should: provide comprehensive road network information predict long-term pavement performance for given funding levels determine backlog requirements

7 2.3 Data Requirements Data Type: The type of data to be collected for road management purposes depends on the use to which it will be put in terms of the managerial level of decision-making involved. The data to be collected can be grouped around various primary functional levels which can be identified as follows: Table 1: Functional Levels of Road Data Functional LevelData Usage SectoralAggregation of data from the RMS, e.g. annual highway statistics (inventory, performance and utilisation, financial NetworkPlanning, programming, budgeting OperationalConstruction, maintenance, traffic, safety Research and Development Study specific, detailed and precise data required for problem diagnosis The amount of detail required for the various functional levels increases progressively from the overall summary statistics at the Sectoral Level, where comparatively broad, low-intensity coverage are required through to study specific requirements at Research and Development Level where very detailed and precise data are required for problem diagnosis and the development of improved practices and methods Data Quality and Detail: The range of detail required can be classified into four Information Quality Levels (IQL) (Paterson and Scullion, 1990) as shown in Table 2. Two parallel trends are apparent in the IQL classification system. Firstly, Global, summary-type data required for sector level statistics is classified as IQL-4 and, as the application progresses to network, project and operations level, the required amount of detail increases, finally reaching IQL-1 for research and development. Secondly, as the IQL level moves from IQL-1 to IQL-4, so the scope for simplicity of data and system requirements and cost implications decrease. Table 2: Use of Information Quality Levels IQLDescriptionApplicationData Collection 1Most detailed, Research, advanced design, Short to limited lengths or isolated comprehensive diagnosis samples; specialised equipment; slow 2Detailed Project design, advanced programming, advanced planning 3Summarised dataprogramming, planning, basic design 4Most summarisedsector/network, simple planning and programming except for advanced automation Limited lengths semi-automated or full coverage advanced automation; high speed Full sample; high speed, low accuracy, semi-automated; or sample processed Manual; semi-automated; processed or estimated

8 2.3.3 Data Collection: Data collection costs tend to be the largest component of the costs of operating a RMS. Thus, prudent choice of data collection methods must be made within a plan of regular monitoring that takes into account the frequency of application of the data and the decision-making cycle, the cost and staff resources required to conduct the surveys and the type of analysis to be applied. Choices to be made in the selection of data collection methods include: Mode of operation - manual, semi-automated, automated - pedestrian, slow or high-speed - independent or composite instrumentation Frequency, spatial coverage and spatial sampling of surveys Mode of administration - centralised - audited process Other considerations - IQL and accuracy required - the size of the network - traffic volumes - technical skills and resources Location Reference System: In order for an integrated RMS to operate efficiently it is essential to have a common Location Reference System (LRS). Thus, notwithstanding the diverse aspects of road management which may be undertaken by different arms of a road authority and the tendency for each arm to operate its own LRS, it is essential that all such systems be reconciled. The fundamental requirements of a LRS are that: it should be so arranged that the system itself is independent of the end user the system should describe the highway network in a manner which is readily intelligible both to man and machine the system must be capable of updating without corrupting existing data or interfering with any user s system 3 THE BOTSWANA ROAD MANAGEMENT SYSTEM 3.1 System Framework The system has been designed to assist the Roads Department in undertaking a wide range of road management functions including: - the construction of new facilities - the adequate maintenance of existing facilities - the upgrading of facilities to meet required standards

9 The essential concept behind the design of the BRMS is that of an integrated, modular, computerised system in which an Information System (Central or Core Database) is linked to and interacts with a number of Decision Support Systems that are both providers and recipients of data from the centre (Vincent et al, 1994). Thus, while each system performs a specific useful function within its own sphere of need, each system should still be seen as part of a larger road management decision making process. NETWORK PLANNING SYSTEM GRAVEL ROAD MANAGEMENT SYSTEM BRIDGE MANAGEMENT SYSTEM GIS CENTRAL DATABASE FUTURE PAVEMENT MANAGEMENT SYSTEM TRAFFIC INFORMATION SYSTEM FUTURE Figure 4: Framework of the Botswana Road Management System 3.2 System Attributes The integrated, modular approach adopted in the design of the BRMS provides the following attributes: offers potential to undertake total infrastructure management in a comprehensive and coherent manner; allows application modules to be introduced separately as and when required without affecting the integrity of the system; benefits from data integration and centralised maintenance and upkeep of a common database; allows operation with less than the full complement of DSSs; offers flexibility for operation of the Decision Support Systems either by individual divisions of the department or by a dedicated Road Management Unit. To achieve a capability for formal economic prioritisation and optimisation, the World Bank s HDM-III model has been incorporated as the basic analytical tool for the RMS. However, in support of the need for a continuous check on the predictive relationships in this model, a number of representative sections on the Public Highway Network are being periodically monitored.

10 3.3 System Components The BRMS offers the capability of accommodating a large number of DSSs which are normally used by a road authority in managing its road system. As illustrated in Figure 4, only a few of these DSSs are currently installed. However, other subsystems will be added in future. 4. TYPICAL APPLICATIONS OF THE BOTSWANA RMS Since the installation of the integrated road management system in Botswana in 1992, the System has been used for a variety of purposes as illustrated below. 4.1 Provision of Road Network Information Information on the extent, usage and condition of the road network is essential at both the strategic and tactical planning levels of a road agency. Modern databases provide powerful methods to interact with data and provide results in table or graphical format summarised to the specifications of the decision maker. Strip-maps of routes, as well as output from the system s geographical information system are utilised to assist in setting and achieving objectives. Figure 5 shows some typical graphical outputs of the BRMS which have proven valuable in marketing strategy to politicians and road users % % % % Very Good 66% Very Poor 1% Poor 2% Fair 7% Good 24% North 54% Western 16% South 30% Traffic Distribution Condition Distribution Network Distribution Figure 5: Typical Graphical Output from the BRMS 4.2 Development of Road Maintenance Strategies Strategy Development at the Network Level: Any authority involved with the management of roads is inevitably faced with the challenge of trying to manage a specified road network to standards set by policy makers (or expected by road users) with a constrained budget. To achieve this objective the following actions are typically carried out: Select optimal maintenance and rehabilitation projects Estimate the long-term consequences of the selected actions Compare the outcome with the set standards Consider alternatives (Adjusted budget, changes in strategy, or lower standards) Finalise the decisions for implementation

11 In developing a strategy for maintenance in Botswana three maintenance policies were modelled in the PMS and the long-term consequences were investigated. The strategies considered consisted of: Strategy 1: A strategy to fix the worst roads first Strategy 2: A strategy to select maintenance action that will result in minimising the long-term Total Transport Cost (TTC). TTC includes both the costs to the Agency and the road users. Details of this approach are described elsewhere (Rohde et al, 1996) Strategy 3: A strategy to select maintenance actions that will maximise the area under a deterioration curve. This approach is similar to maximising costeffectiveness as described by Haas et al (1994). For illustrative purposes, the outcome of pursuing the alternative strategies indicated above, for a given budget allocation of P30 million, was evaluated in terms of the long-term outcome of the following: a) Network Condition Figure 6a indicates that, in terms of the average travelled condition of the road network, the long-term outcome of Strategies 2 and 3 is clearly preferable to Strategy 1. The prediction of this type of combined performance index is a valuable communication tool to convey information to decision makers. However, the aggregate nature of the index reduces its suitability for use beyond the network level selection of funding and maintenance strategies. b) User and Total Transport Costs Figure 6b and 6d indicate that, in terms of average vehicle operating costs over a 10 year period and annual excess user costs respectively, Strategies 2 and 3 are again clearly preferable to Strategy 1. In this regard, Cox (1994) has found that, worldwide, there is a growing realisation that investment decisions which have traditionally been based primarily on network needs and engineering standards in some countries, should be based on total life cycle costs including, importantly, user and vehicle operating costs. c) Asset Value The preservation of the asset value of a road network can provide a useful basis for selecting and evaluating alternative investment strategies. Figure 7 shows this concept in which the value of any road is calculated as the value it would have it were new (replacement value) minus the cost of taking it from its present condition (which is deficient due to some degree of deterioration) to the very good condition. The amount subtracted corresponds to the cost of eliminating any deficiency the road may have. Figure 6c shows that, in terms of the estimated change in asset value over a 15 year period, Strategy 3 is clearly preferable to strategies 1 and 2.

12 6b : AVERAGE VEHICLE OPERATING COST OVER 10 YEARS Average Travelled Condition 6a: ESTIMATED AVERAGE TRAVELLED CONDITION Pula per Travelled km Fix Worst First Area Under Curve TTC Low Volume High Volume 6c : ESTIMATED CHANGE IN ASSET VALUE OVER 15 YEARS d: ESTIMATED ANNUAL EXCESS USER COST P' Excess User Cost (P Millions) Fix Worst First Area Under Curve TTC Area Under Curve TTC Fix Worst First Figure 6: The long-term Outcome of Various Maintenance Policies on Road Condition and Road Users

13 What the above examples do illustrate quite vividly is that it is very important for any road agency to be fully aware of the long-term consequences of pursuing any particular investment strategy. They also illustrate the detrimental consequences of not obtaining optimal funding for maintenance of their road networks in relation to the strategy being pursued. In the examples used to illustrate these points, it can be concluded that an annual budget of P30 million is not adequate to maintain the road network in its current condition if the maintenance strategy being pursued is to fix the worst roads first. In the long term, such a strategy will result in loss of asset value and an accelerating increase in vehicle operating and user costs resulting in increased transport costs. Very Good Good Fair Poor Degree of Deterioration Very Poor Maximum Theretical Asset Value - Cost of Restoring to Very Good Con ditoion = Asset Value of a Road Figure 7: The Asset Value of a Road (ECLAC, 1992) Strategy Development at the Project Level The development of a life cycle maintenance strategy on each road link of the road network is also available from the system. The optimal strategy for a link is selected using an incremental benefit-cost technique (Shahin et al, 1985). In the analysis, the life-cycle costs and benefits associated with all the possible strategies on a link are predicted. The benefit can be defined in monetary terms (the savings in user cost minus the agency costs) or in non-monetary terms (the area under a condition curve multiplied by traffic). Figure 8 shows a typical cost benefit plot extracted from the PMS (Deighton 1995) for a specific link. On this section, 10 possible strategies are considered. If the costs and benefits of each strategy are plotted the upper-most points on the graph can be connected so that no points exist above the connected line. This segmented line is called the "economic efficiency frontier" and connects the strategies that will maximise the benefit for any cost. In the example shown a strategy to seal the road in 1998 was selected for a network budget of 30 million while a rehabilitation in 2004 will be the optimal strategy under a less constrained budget of 45 million. If there are no limits set on the maintenance budget a heavy rehabilitation in 2006 will be the optimal strategy (i.e., maximising the benefits).

14 4,000,000 3,500,000 Light Rehab 2004 Light Rehab 2005 Heav Rehab 2006 Heav Rehab ,000,000 2,500,000 2,000,000 Seal 1998 Seal 1999 Seal 2000 Seal Modified 2000 Seal Modified ,500,000 Routine Only 1,000,000 Strategies Selected Under 45 mill Budget 500,000 Efficiency Frontier Selected Under 30 mill Budget Do-Nothing Selected Under No Constraints , , , , , ,000 COSTS (Pmill) Figure 8: Typical Cost-Benefit Plot of a Link 4.3 Determination of Optimal Budgets In selecting an optimal budget the long-term consequences as described in section 4.2 above should also be considered. Figure 9 shows typical output from the BRMS used in selecting an appropriate budget for maintenance and rehabilitation of the paved road network. In the plots the average network condition and backlog (proportion of the network in poor and very poor condition) associated with different funding levels are shown. From this analysis it is evident that a annual budget of approximately 45 million is required to maintain the network to its current condition Average Condition Backlog (%) Year Year P17 mill P24 mill P35 mill P41 mill P17 mill P24 mill P35 mill P41 mill 5. SUMMARY Figure 9: Future Condition for Different Budget Levels Increased demands for economic efficiency in the use of scarce public funds has led to the development of systems approaches to road management in many countries culminating in the increasing use of computerised Road Management Systems. The modular, integrated framework used for the development of the Botswana Road Management System (BRMS) is based on a strategy developed within the Southern

15 Africa Transport and Communications Commission (SATCC) (Pinard et al, 1994). This framework has provided the flexibility to undertake various aspects of road management in a structured, comprehensive and cost-effective manner and has permitted the phased introduction of additional Decision Support Systems to match the resources and requirements of the Roads Department. The BRMS has been successfully operated at three management levels, namely policy/executive, planning and execution, and has provided a powerful basis for undertaking strategic, tactical and operational planning within the department. This has allowed Roads Department personnel to quantify funding requirements for maintaining various elements of the road network in an optimal manner and, importantly, to demonstrate the economic consequences of not obtaining such funding. The successful operation of the BRMS has emphasised not only the importance of top management support for such an undertaking but also the need to have adequate staffing resources and to undertake continuing staff training in the use of the system. However, the potential offered by the BRMS for ensuring that available funds are optimally spent is probably a small price to pay for the use of a tool which is increasingly becoming the nerve centre of most road agency operations. REFERENCES 1. Sinha, K C and Fwa, T F., On the Concept of Total Highway Management. TRR 1229, Transportation Research Board, Washington D.C., USA. 2. Paterson, W.D.O and Scullion, T., Information Systems for Road Management: Draft Guidelines on System Design and Data Issues. Technical paper INU77, Infrastructure and Urban Dedvelopment Department, World Bank, Washington, D.C. 3. Vincent, S P R, Leach, A S, McPherson K and Kerali, H R., Development of Road Management Systems in Southern Africa. Proceedings of the 3 rd International Conference on Managing Pavements, Vol 1 pp San Antonio, Texas. 4. Rohde, G T, Pinard, M I and Sadzik, E., Long-term Network Performance - A function of Maintenance Strategy. Proceedings of Combined 18 th ARRB Transport Research Conference Transit NZ Land Transport Symposium, Christ Church, New Zealand, Vol. 4, pp Haas, R, Hudson, W R and Zaniewski, J., Modern Pavement Management, Kriegeler Publishing Co. Florida, USA. 6. Cox J B., Refocusing Road Reform, Business Council of Australia, Melbourne, Victoria, Australia. 7. Economic Commission for Latin America and the Caribbean., Roads: A New Approach for Road Network Management and Conservation. Santiago, Chile.

16 8. Shahin, M Y, Kohn, S D, Lytton, R L and McFarland, W F., Pavement Budget Optimisation Using the Incremental Benefit-Cost Technique. Vol. 3, Proc. North American Pavement Management Conference, Toronto. 9. Deighton and Associates., dtims Users Manual, Deighton Associates, Bowmanville, Ontario, Canada. 10. Pinard, M I, Paterson, W D O and Mbvundula, W D., Strategy for Development and Implementation of Road Management Systems in Southern Africa Development Community Region. Proceedings of the 3 rd International Conference on Managing Pavements, Vol 2 pp San Antonio, Texas. Keywords: Road, Pavement, Maintenance, Management, Systems.