Using Risk Analysis to Prioritise Road-Based Intelligent Transport Systems (ITS) in Queensland Katherine Amelia Johnston BE Civil (Honours) School of Urban Design Faculty of Built Environment and Engineering Queensland University of Technology Masters by Research (BN72) 2006 Keywords Intelligent Transport Systems, evaluation, incident management, variable message signs, prioritisation, risk analysis, decision-making Abstract With perpetual strains on resources, road agencies need to develop network-level decision-making frameworks to ensure optimum resource allocation. This is especially true for incident management services and in particular variable message signs (VMS), which are relatively immature disciplines compared to traditional road engineering. The objective of incident management and VMS is to minimise the safety, efficiency, reliability and environmental impacts of incidents on the operations of the transport system. This may be achieved by informing travellers of the incidents so they can adapt their behaviour in a manner that reduces community impacts, such as lateness and the associated vehicle emissions, unreliability of travel times, as well as secondary accidents due to incidents. Generally, road authorities do carry out needs assessments, but qualitatively in many cases. Therefore, this masters research presents a framework that is systematic, quantitative and relatively easy to implement. In order to prioritise VMS infrastructure deployment, a risk management approach was taken that focuses on minimising the impacts on, and costs to the community. In the framework and case study conducted, safety, efficiency and reliability, and environmental impacts are quantified using an economic risk management approach to determine an overall risk score. This score can be used to rank road sections within the network, indicating the roads with the highest risk of incident network impacts and therefore the roads with the highest need for intervention. A cost-effectiveness based risk-reduction ranking can then be determined for each incident management treatment type, comparing the net risk with treatment to that without treatment, and dividing by the net present value of deployment. The two types of ranking, pure risk and cost-effectiveness based risk reduction, will help to minimise the network impacts on the community and optimise resource allocation. i Table of contents KEYWORDS I ABSTRACT I TABLE OF CONTENTS II LIST OF TABLES VI LIST OF FIGURES VII LIST OF ABBREVIATIONS VIII LIST OF ABBREVIATIONS VIII LIST OF NOTATIONS IX STATEMENT OF ORIGINAL AUTHORSHIP XI ACKNOWLEDGEMENTS XI 1 INTRODUCTION 1 1.1 Background 1 1.2 Project scope 3 1.3 Structure of thesis 3 1.4 Further project documentation 4 2 REVIEW OF TRAFFIC OPERATIONS AND ITS 6 2.1 Objectives of traffic operations and ITS 6 2.2 Traffic efficiency 8 ii 2.3 Safety 9 2.4 Definition of ITS systems and services 10 2.5 Evolution of ITS planning and deployment 11 2.6 Benefits of ITS systems and services 12 2.7 Risks of ITS 15 2.8 Incident management 15 3 REVIEW OF ITS EVALUATION 17 3.1 Why does ITS differ from conventional road projects 18 3.2 ITS Evaluation methods 19 3.2.1 Benefit-cost analysis 19 3.2.2 Multi-criteria analysis 20 3.2.3 Cost effectiveness analysis 22 3.2.4 System analysis 22 3.2.5 Benchmarking 28 3.2.6 Risk analysis 30 3.3 Incident impacts 30 3.3.1 Safety 31 3.3.2 Economic 32 3.3.3 Environmental 32 4 REVIEW OF CURRENT PRACTICE ON EVALUATION FRAMEWORKS 34 4.1 Questionnaire development 35 4.2 Findings 36 4.2.1 Respondent characteristics 36 4.2.2 Organisational decision-making attributes 38 4.3 Conclusions and further research 40 iii 4.4 Research focus 40 5 USING RISK ANALYSIS TO EVALUATE INCIDENT MANAGEMENT DEPLOYMENT 42 5.1 Purpose of framework 42 5.2 Overview of framework 44 5.3 Theoretical basis of framework 46 5.4 Monetising ITS impacts 50 5.4.1 Safety impacts 51 5.4.2 Reliability impacts 52 5.4.3 Environmental impacts 56 5.5 Worked example 58 5.5.1 Situation 58 5.5.2 Safety impact assumptions and calculation 58 5.5.3 Reliability impact assumptions and calculation 59 5.5.4 Environmental impact assumptions and calculation 60 5.5.5 Total incident calculation 61 6 CASE STUDY 62 6.1 Introduction 62 6.2 Assumptions 63 6.3 Results and discussion 66 6.3.1 Sensitivity towards assumption of travel time cost 69 7 CONCLUSIONS AND FURTHER RESEARCH 72 7.1 Conclusions 72 7.1.1 Literature and current practice reviews 72 7.1.2 Methodology 73 7.1.3 Case study 73 iv 7.2 Further research 73 7.3 Recommendations 75 APPENDIX A. WORK PRACTICES REVIEW – RAW DATA AND QUESTIONNAIRE 76 APPENDIX B – CASE STUDY SPREADSHEET 85 BIBLIOGRAPHICAL REFERENCES 86 v List of Tables Table 2-1 Examples of highway agencies' traffic operation objectives.......................7 Table 2-2 Comparison of ITS categories from Austroads, Caltrans and Ertico ........10 Table 2-3 Objective or benefit categories for ITS (Austroads, 2003a)......................14 Table 3-1 Examples of traffic performance indicators by goal or objective..............24 Table 4-1 Number of decision-making techniques stated at various levels of the organisation ........................................................................................................38 Table 4-2 Number of information types used at various levels of the organisation ..39 Table 5-1 Framework definitions...............................................................................46 Table 5-2 Consequence impact categories for incident management ........................47 Table 5-3 Number of significant days for each road type..........................................48 Table 5-4 Safety impact values (Isx) from Austroads (2004a) ..................................52 Table 5-5 Travel time values by incident type based on Table 3.9 in Austroads (2004a) ...............................................................................................................54 Table 5-6 Proportion of total passenger car trips by purpose ....................................54 Table 5-7 Percentage of road closed or blocked factor (L') based on Table A-10 in Stockton et al (2003) ..........................................................................................56 Table 5-8 Environmental impact values (IG) for passenger vehicles .........................57 Table 5-9 Environmental impact values (IG) for freight vehicles .............................57 Table 5-10 Safety impact parameters for example.....................................................58 Table 5-11 Reliability impact parameters for example..............................................59 Table 5-12 Environmental impact parameters for example......................................60 Table 6-1 VMS benefits based on literature review...................................................65 Table 6-2 Pure risk ranking for state-controlled roads in the South Coast Hinterland District using 2002 data......................................................................................67 Table 6-3 Cost effectiveness ranking for state-controlled roads in the South Coast Hinterland District using 2002 data ...................................................................68 Table 6-4 Cost effectiveness ranking for state-controlled roads in the South Coast Hinterland District using 2002 data with constant values of travel time ...........70 vi List of Figures Figure 2-1 Peak-period congestion (travel time index) trends by U.S. population group (Cambridge Systematics Inc, 2004) 8 Figure 2-2 Sources of congestion (Cambridge Systematics Inc, 2004) 9 Figure 4-1 Extract from current practices questionnaire 35 Figure 4-2 Number of respondents by location 36 Figure 4-3 Number of respondents by organisation type 37 Figure 4-4 Number of respondents by organisation and personal responsibility 37 Figure 5-1 Risk analysis framework for incident management prioritisation 45 Figure 5-2 Example of relationship between lateness and travel time value 55 Figure 6-1 Map of South Coast Hinterland District (SCHD) 63 vii List of Abbreviations AADT Annual average daily traffic ARRB Australian Road Research Board AHP Analytical hierarchy process BCA Benefit-cost analysis BCR Benefit-cost ratio BTRE Bureau of Transport and Regional Economics CEA Cost-effectiveness analysis CER Cost-effectiveness ratio DOT Department of Transportation DoTaRS Australian Department of Transport and Regional Services DMR Queensland Department of Main Roads GSM Global system for mobile IRR Internal rate of return ITS Intelligent Transport Systems IVHS Intelligent Vehicle and Highway Systems MCA Multi-criteria analysis NPV Net present value SCHD South Cost Hinterland District UK United Kingdom USDOT United States Department of Transportation VMS Variable Message Sign WIM Weigh-in-motion viii List of Notations AADT Average annual daily traffic C Average consequence of an event ΔC Reduced cost of consequences for road segment y Cafter Cost of consequences after treatment Cbefore Cost of consequences before treatment CER Cost effectiveness ratio for road segment y CGx Cost of environmental consequences for incident x in dollars Ci Consequence cost of impact event i Cjk Merit score for outcome j and criterion k CRx Cost of lateness (reliability impacts) for incident x in dollars CSx Cost of secondary accidents (safety impacts) for incident x in dollars CT Total annual cost of consequences for road segment y in dollars CT Average incident consequence for road segment y D Estimated lateness caused by incident x in hours Directional distribution factor