Road Safety
Guide to Road Safety Part 2: Safe Roads
- Publication no: AGRS02-21
- ISBN: 978-1-922382-60-3
- Published: 16 July 2021
- Edition: 1.0
- PDF (free) Download
Austroads' Guide to Road Safety has been developed to provide an overview of road safety and road safety practices in Australia and New Zealand.
Part 2 of the guide is designed to help practitioners minimise the risk of road crashes including run-off-road, intersection and head-on crashes and to implement countermeasures to achieve a safe road system.
The guide contains practical, hands-on advice to help practitioners investigate and treat locations on the road system which are experiencing crashes, including identifying crash locations, diagnosing the crash problem and its causes, selecting a countermeasure which targets the problem, designing a safe remedial treatment and establishing its cost-effectiveness.
The guide also provides information on sources of road crash data and how engineering improvements fit into an overall road safety strategy.
This guide is intended for road authorities and road safety practitioners to use when considering potential road safety infrastructure improvements and should be read in conjunction with all other parts of the Guide to Road Safety.
At the time of publication, the 2021-2030 National Road Safety Strategy has not yet been released. A future project will update this Guide so that it reflects the Strategy.
- 1. Introduction
- 1.1 Purpose of the Guide
- 1.2 Road Safety in the Road System Management Process
- 1.3 Network and Corridor Planning
- 1.4 Program Development
- 1.5 Project Scoping and Development
- 1.6 Project Implementation and Review
- 1.7 Network Operation
- 1.8 How to Use this Guide
- 1.8.1 Proactive crash prevention
- 2. Reactive and Proactive Road Safety Approaches
- 2.1 Risk Assessment and Management: Linking ‘Reactive’ and ‘Proactive’ Safety Approaches
- 2.2 Developing a Program to Address High Crash Risk Locations
- 2.3 Taking Action to Improve Road Safety
- 2.3.1 The countermeasure approach and the role of infrastructure
- 2.3.2 The Safe System approach
- 2.3.3 Crash risk
- 2.3.4 What is a crash location?
- 2.3.5 Treating crash locations
- 2.3.6 Who should investigate crash locations and develop solutions?
- 2.3.7 What are road safety engineering skills?
- 2.4 Steps in the Crash Location Treatment Process
- 2.4.1 The steps
- 3. Road Crash Data
- 3.1 Data Sources and Codes
- 3.2 Sources of Crash Data
- 3.2.1 Primary data sources for crash reduction programs
- 3.2.2 Other data sources
- 3.3 Technology Available for Data Collection
- 3.3.1 To improve the accuracy of location information
- 3.3.2 To improve the accuracy and completeness of crash data
- 3.4 Limitations and Accuracy of Crash Data
- 3.4.1 Coding of crash types – DCAs, RUMs and VMCs
- 4. Identifying Crash Locations
- 4.1 Defining the Locations
- 4.1.1 Deciding on a time period
- 4.1.2 Criteria for selecting locations to investigate for countermeasures
- 4.1.3 Using a threshold method
- 4.1.4 Chance variation
- 4.2 Intersections
- 4.3 Routes
- 4.4 Areas of the Road Network
- 4.5 Mass Action
- 4.1 Defining the Locations
- 5. Diagnosing the Crash Problem and Selecting Treatments
- 5.1 Analysis of Crash Data and Interpretation
- 5.1.1 Examine crash types (DCA or other similar codes)
- 5.1.2 Construct a crash factor matrix
- 5.1.3 Draw a collision diagram
- 5.1.4 Look for common factors
- 5.1.5 Writing the preliminary report
- 5.2 Other Relevant Information
- 5.3 Site Investigation
- 5.3.1 Drive through the location
- 5.3.2 Inspect the location
- 5.3.3 Consider driver behaviour
- 5.3.4 Identifying the cause of the crash
- 5.4 Identification of Crash Causation and Crash Severity Factors
- 5.4.1 Draw conclusions
- 5.4.2 Write a crash summary report
- 5.4.3 Applying the process to area studies and mass action programs
- 5.5 Countermeasure Selection and Design
- 5.5.1 What is a safe road environment?
- 5.5.2 Safe System treatments
- 5.5.3 Speed management
- 5.5.4 Enforcement
- 5.5.5 Match the solutions to the problems
- 5.5.6 Select the solutions
- 5.6 Crash Modification Factors
- 5.6.1 Multiple treatments
- 5.6.2 Step 1: Select the most appropriate countermeasure/s
- 5.6.3 Step 2: Apply CMFs
- 5.7 Implementing the Treatment
- 5.7.1 Designing a safe remedial treatment
- 5.7.2 Implementing the treatment
- 5.1 Analysis of Crash Data and Interpretation
- 6. Economic Appraisal
- 6.1 Cost of Crashes and Remedial Treatment Options
- 6.1.1 Treatment options
- 6.1.2 Cost of crashes
- 6.2 Calculating the Costs and Benefits
- 6.2.1 Key parameters
- 6.2.2 Discounting
- 6.2.3 Calculating costs and benefits
- 6.3 Ranking the Treatment of Crash Locations
- 6.3.1 A useful checklist
- 6.4 Presenting the Results
- 6.5 Applying to Routes, Areas and Mass Actions
- 6.5.1 Routes and areas
- 6.5.2 Mass actions
- 6.6 Post-completion Evaluation
- 6.7 Alternatives to Benefit Cost Approach
- 6.7.1 The goals achievement approach to project appraisal
- 6.7.2 Cost-effectiveness
- 6.1 Cost of Crashes and Remedial Treatment Options
- 7. Monitoring and Evaluation
- 7.1 Monitoring and Evaluation Methods
- 7.1.1 Statistical analysis
- 7.2 Issues for Consideration
- 7.2.1 Planning before treatment for monitoring afterwards
- 7.2.2 Threats to the validity of evaluation
- 7.1 Monitoring and Evaluation Methods
- 8. Preparing a Crash Report
- 9. Harm Minimisation at Intersections
- 9.1 Determinants of Injury at Intersections
- 9.1.1 Post impact vehicle trajectories
- 9.2 Innovation Towards Harm Minimisation at Intersections
- 9.2.1 Roundabouts
- 9.2.2 Innovation in intersection design
- 9.1 Determinants of Injury at Intersections
- 10. Harm Minimisation with High Speed Lane Departures
- 10.1 Reducing the Harm of Road Departures
- 10.1.1 Treatment hierarchy for road departures
- 10.1.2 Clear zones
- 10.2 Keeping Vehicles on the Road
- 10.2.1 Delineation
- 10.2.2 Road design elements
- 10.3 Types of Hazards and their Treatments
- 10.3.1 Rigid objects
- 10.3.2 Embankments and cuttings
- 10.3.3 Open drains
- 10.3.4 Bodies of water
- 10.3.5 Kerbs
- 10.4 Safety Barriers
- 10.4.1 Decision to install a safety barrier
- 10.4.2 Barrier failures
- 10.4.3 Barriers and motorcyclists
- 10.4.4 Safety barrier types
- 10.4.5 Layout and design of safety barriers
- 10.4.6 Continuous safety barriers (protected corridors)
- 10.4.7 Work zone barriers
- 10.5 Reducing the Harm from Head-on Crashes
- 10.5.1 Treatment hierarchy for head-on crashes
- 10.5.2 Centreline barriers on undivided roads
- 10.5.3 Flexible barriers on divided roads
- 10.5.4 Wide centreline treatment
- 10.6 Safe Rural Road Stereotypes
- 10.7 New Thinking About Road Corridors - Movement and Place
- 10.1 Reducing the Harm of Road Departures
- 11. Road Safety for Regional and Remote Areas
- 11.1 Safe Roads – Road Safety Risk Factors
- 11.1.1 Road condition
- 11.1.2 Road design
- 11.1.3 Roadside environment
- 11.1 Safe Roads – Road Safety Risk Factors
- References
- Appendix A Crash Codes for Australian Jurisdictions
- Appendix B Example Blank Factor Matrix Form
- Appendix C Examples
- C.1 Practical Example 1: Investigation of High Crash Locations
- C.1.1 Example 1A
- C.1.2 Example 1B
- C.1.3 Example 1C
- C.1.4 Example 1D
- C.2 Practical Example 2: Chance Variation
- C.3 Practical Example 3: Writing a Preliminary Report
- C.4 Practical Example 4: Applying Crash Modification Factors
- C.4.1 Example 4A
- C.4.2 Example 4B
- C.5 Practical Example 5: Road Safety Audit of a Remedial Treatment
- C.6 Practical Example 6: Selecting the Countermeasures
- C.7 Practical Example 7: Economic Appraisal
- C.7.1 Example 7A: (based on Ogden 1996)
- C.7.2 Example 7B (based on Andreassen 1992a, p.5)
- C.8 Practical Example 8: Monitoring
- C.1 Practical Example 1: Investigation of High Crash Locations
- Appendix D Detailed Case Study
- D.1 Step-by-step Process in the Investigation and Treatment Process
- D.1.1 Background
- D.1.2 Deciding which road sections and intersections are to be included
- D.1.3 Deciding on the time period
- D.2 Obtaining all the Relevant Information
- D.2.1 Data discrepancies
- D.3 Constructing a Factor Matrix and Identifying Common Factors and Clustering of Crashes
- D.4 Drawing a Collision Diagram and Identifying Clusters of Crash types at Locations
- D.5 Summarising the Factors Identified from the Crash Listings, Factor Matrix and Collision Diagram
- D.5.1 Intersections
- D.5.2 Road sections
- D.5.3 Summary of factors
- D.6 Inspecting the Site
- D.6.1 Observations from driving the site
- D.6.2 Observations from inspecting the site on foot
- D.6.3 Observed driver behaviour
- D.6.4 Confirm speed limit
- D.6.5 Discussion
- D.7 Selecting the Countermeasures
- D.7.1 Loss of control and head-on crashes
- D.7.2 Fixed object crashes
- D.7.3 Other intersection crashes
- D.7.4 Other issues
- D.8 Designing a Safe Remedial Treatment
- D.9 Economic Appraisal
- D.1 Step-by-step Process in the Investigation and Treatment Process
- Appendix E Crash Modification Factors
- Appendix F Confidence Limits and Changes in Critical Mean
- Appendix G Monitoring Techniques and Allowing for Regression-to-the-mean
- G.1 Monitoring Techniques
- G.1.1 Experimental design
- G.1.2 Before and after studies
- G.1.3 Comparisons using control sites
- G.2 Regression-to-the-mean
- G.2.1 A worked example of correction for regression-to-the-mean (from Ogden 1996, p 458)
- G.1 Monitoring Techniques
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