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Infrastructure Improvements to Reduce Motorcycle Casualties 2016-07-16

technical findings of a two-year study which sought to identify effective infrastructure improvement

  1. Mouth
    This report presents the technical findings of a two-year study which sought to identify effective infrastructure improvements to reduce motorcycle crash risk and crash severity, based on how riders perceive, respond and react to infrastructure they encounter.

    The project commenced with a literature review of national and international guides, publications and research papers, which also enabled the identification of knowledge gaps and areas where further detail was required. A crash analysis was undertaken to demonstrate the relationship between motorcycle crashes, travel period, vehicle configuration (i.e. motorcycle only and multiple vehicle crashes involving a motorcycle), road geometry, road layout (e.g. intersection type) and crash types. For comparative purposes, vehicle crashes at the same location were also analysed.

    Explanations of why, and how, road infrastructure elements influence motorcycle crash risk were researched and are provided within this report. This primarily involved identifying how the design and condition of road infrastructure elements can influence either the likelihood of a crash occurring or the resulting severity of a crash. Where a number of elements that would increase the likelihood or severity of a crash were present concurrently, the proportionate increase in risk was demonstrated using the AusRAP model.

    The study has built up a compendium of treatments, presented in such a way that engineering decisions to manage these elements can be justified, even if outside of existing design warrants, and asset management and maintenance practice.

    The research highlights that motorcycles should be identified as an individual road user group and considered as a ‘design vehicle’ during road design and asset management and maintenance practices.

    It is concluded that motorcycle crash risk can be managed, but requires changes in practice, in design, asset management funding and routine maintenance performance contracts. One example is in the identification of road sections and/or routes that pose the highest crash risk to motorcyclists, so that they can be managed and maintained appropriately. In addition, the author advocates proactive motorcycle specific network safety assessments and road safety audits, as well as fine-tuning in design parameters for roads carrying significant volumes of motorcyclists (e.g. horizontal geometry, sight lines, lane and shoulder width, intersection types, intersection quality and controls). It is also suggested that the range and detail of mitigation measures be expanded.




    Table of Contents
    Summary1. Introduction
    • 1.1 Background
    • 1.2 Objective
    • 1.3 Method
    • 1.4 Approved Safety Barrier Products
    2. Literature Review
    • 2.1 Introduction
    • 2.2 Crash Contributory Factors
    • 2.2.1 Characteristics of Motorcycle Crashes
    • Motorcycle crashes vs motorcycle registration
    • Influence of time, day, month of year and weather conditions
    • Locations and road types
    • Single and multi-vehicle crash types
    • Engine capacity
    • Human factors
    • Excessive speed, alcohol and drugs
    • At-fault vehicle
    • Group riding
    • 2.2.2 Contributory Crash Factors Relating to Road Infrastructure and Design
    • Roadside hazards
    • Pavement condition
    • Pavement markings and delineation
    • Intersections
    • Horizontal curvature and alignment
    • Posted speed limits
    • Motorcycle braking systems
    • 2.3 Treatments
    • 2.3.1 Roadside Hazards
    • 2.3.2 Pavement Condition
    • 2.3.3 Intersections
    • 2.3.4 Horizontal Curvature
    • 2.4 Case Studies
    • 2.4.1 Case Study: Motorcycle Safety Route Review – New South Wales
    • 2.4.2 Case Study: Road Safety Barrier Treatments – South Australia
    • 2.4.3 Case Study: Motorcycle-friendly Barrier Systems – EuroRAP
    • 2.4.4 Case Study: Motorcycle Blackspot Program in Victoria
    • 2.4.5 Case Study: Motorcycle Blackspot Program in Victoria – Update July 2015
    • 2.5 Conclusions
    3. Crash Analysis
    • 3.1 Summary of Crash Rates
    • 3.1.1 Overall Crash Rates
    • 3.1.2 Injury Crash Rates
    • 3.2 Multiple and Single Vehicle Crashes
    • 3.3 Commuting and Recreational Travel Crashes
    • 3.3.1 All Crashes by Travel Purpose
    • 3.3.2 Crashes Involving Vehicles only by Travel Purpose
    • 3.3.3 Crashes Involving Motorcycles by Travel Purpose
    • 3.3.4 Vehicle and Motorcycle Crash Comparison by Travel Purpose
    • 3.4 Relationship between Road Geometry, Intersections and Crashes
    • 3.4.1 All Crashes by Road Feature
    • 3.4.2 All by Road Feature and Travel Purpose
    • 3.4.3 Single Vehicle Crashes by Road Feature and Travel Purpose
    • 3.4.4 Multiple Vehicle Crashes by Road Feature and Travel Purpose
    • 3.4.5 Single and Multiple Vehicle, Motorcycle Crash Comparison by Road Feature
    • 3.5 Mid-block Crashes
    • 3.5.1 Mid-block Vehicle and Motorcycle Crashes by Horizontal Geometry
    • 3.5.2 Mid-block Vehicle and Motorcycle Crashes by Vertical Geometry
    • 3.5.3 Mid-block Motorcycle Crashes by Horizontal and Vertical Geometry
    • 3.5.4 Mid-block Crashes by Crash Type (Crash Nature, DCA or Movement Code)
    • 3.6 Intersection Crashes
    • 3.6.1 All Crashes by Intersection Type
    • 3.6.2 Motorcycle Crashes by Intersection Type and Travel Purpose
    • 3.6.3 Intersection Motorcycle Crashes by Crash Code
    • 3.6.4 Intersection Motorcycle Crashes by Crash Code and Travel Purpose
    • 3.6.5 Intersection Motorcycle Crashes by Intersection Control
    • 3.6.6 Intersection Motorcycle Crashes by Intersection Control and Travel Purpose
    • 3.7 Key Findings of the Crash Analysis
    • 3.7.1 Vehicle and Motorcycle Crash Rates
    • 3.7.2 Single and Multiple Vehicle Crashes
    • 3.7.3 Commuting or Recreational Period Crashes
    • 3.7.4 Crashes by Road Feature
    • 3.7.5 Mid-block Crashes
    • 3.7.6 Intersection Crashes
    4. Road Infrastructure as a Crash Factor
    • 4.1 Infrastructure Effects on Motorcycle Performance
    • 4.1.1 Operating a Motorcycle
    • 4.1.2 Operating a Motorcycle and the Interaction with Road Infrastructure
    • 4.2 Crash Factors by Road Engineering Discipline
    • 4.3 Assessing Motorcycle Likelihood and Severity using AusRAP
    • 4.3.1 Risk Factors – Difference between Vehicles and Motorcycles
    • 4.3.2 Star Rating Score
    • 4.4 Midblock Crash Likelihood
    • 4.4.1 Road Alignment
    • Horizontal curves
    • Motorcycle riding path
    • Increased crash risk on horizontal curves
    • Vertical curves
    • 4.4.2 Sight Distance
    • Sight distance effects on the riding path selected
    • Sight distance effects on identifying road surface hazards and vehicles over the centre line
    • 4.4.3 Carriageway Width
    • Lane width
    • Shoulder width
    • Design width and usable width
    • 4.4.4 Delineation and Signage
    • Defining the alignment
    • Warning, hazard and information signage
    • Vanishing point
    • 4.4.5 Curve Quality
    • Curve warning signs
    • Chevron alignment markers
    • Guide posts, linemarking and RRPMs
    • 4.4.6 Road Surface
    • Surface friction (‘grip’)
    • Surface drainage
    • Surface hazards
    • 4.4.7 Overtaking Provisions
    • 4.5 Intersection Crash Likelihood
    • 4.5.1 Intersection Type
    • Roundabouts
    • T-junctions
    • Cross intersections
    • Centre medians
    • Railway and tram crossings
    • Signalised intersections
    • 4.5.2 Intersection Sight Distance and Visibility
    • Visibility of motorcycle
    • Intersection sight distances
    • Observation angles
    • 4.5.3 Turning Provision
    • Turning from the major (through) road
    • Turning from the side (intersecting) road
    • Signalised right turns
    • 4.5.4 Intersection Location
    • 4.5.5 Road Surface
    • Surface friction
    • Surface drainage
    • Surface hazards
    • 4.5.6 Carriageway Width
    • Manoeuvring width
    • Lane filtering
    • 4.5.7 Lighting, Delineation and Signage
    • 4.5.8 Intersection Signage
    • 4.6 Crash Severity
    • 4.6.1 Collision Speed
    • Collision speed and posted speed limits
    • Single vehicle crash
    • Multiple vehicle crash
    • 4.6.2 Surface Area
    • 4.6.3 Impact Absorption
    • 4.6.4 Impact Angle
    • 4.6.5 Roadside Objects
    • Roadside furniture
    • Sharp edges
    • Safety barriers
    • Utility services
    • Drainage
    • Natural environment and landscaping
    • 4.7 Total Crash Risk
    • 4.7.1 Crash Likelihood
    • 4.7.2 Crash Severity
    5. Mitigation Measures
    • 5.1 Mitigation Measures and Current Practice
    • 5.2 Implementation Strategies
    • 5.2.1 Existing Practices
    • 5.2.2 Proactive Risk Assessments
    • 5.2.3 Motorcycle Specific Guidance for Practitioners
    • 5.3 Additional Treatments to Reduce Motorcycle Crash Risk
    • 5.3.1 Mid-block Treatments
    • 5.3.2 Intersection Treatments
    • 5.3.3 Motorcycle Specific Signage
    • Crash Zone Signage
    • Look-for-bikes signage
    • Road condition signage
    • 5.3.4 Roadside Hazard Management
    6. Stakeholder Consultation
    • 6.1 Background
    • 6.2 Workshops and Consultations
    • 6.3 Questionnaire Findings
    • 6.3.1 Comments on Preliminary Findings
    • 6.3.2 Midblock Crash Likelihood
    • Sight distance
    • Road alignment
    • Travel period and traffic volume
    • Travel lane surface, conditions and hazards
    • Shoulder surface hazards
    • Formation width
    • Signage and delineation
    • Curve quality
    • Average speed and overtaking provisions
    • Roadworks
    • Combination of factors
    • Safety barriers
    • Other
    • 6.3.3 Intersection Crash Likelihood
    • Visibility
    • Intersection type
    • Turning provisions
    • Horizontal geometry
    • Advanced signage
    • Line of sight
    • Travel lane surface texture, condition, and hazards
    • Carriageway width
    • Lane filtering
    • 6.3.4 Available Technical Guidance
    • 6.3.5 How Motorcyclists are Catered for in Design, Asset Management and Maintenance
    • 6.3.6 Raised Awareness from Preliminary Findings
    • 6.4 Workshop Findings
    • 6.4.1 Review of Project Findings
    • 6.4.2 Review of the Proposed Mitigation Measures
    • Managing existing roads
    • Designing for motorcycles
    • Hierarchy of control
    • 6.4.3 Recommended Changes to the Austroads Guides
    7. Austroads Guide Review
    • 7.1 Austroads Guide to Road Design, Guide Review
    • 7.2 Austroads Guide to Road Safety, Guide Review
    • 7.3 Austroads Guide to Pavement Technology, Guide Review
    • 7.4 Austroads Guide to Traffic Management, Guide Review
    • 7.5 Austroads Guide to Asset Management, Guide Review
    • 7.6 Austroads Guide to Road Transport Planning, Guide Review
    8. Safety Assessment of Mitigation Measures
    • 8.1 Assessment Process
    • 8.1.1 AusRAP and Mitigation Measures
    • 8.1.2 Study Network
    • 8.1.3 Crash Data
    • 8.1.4 Road Infrastructure Data
    • 8.2 Results
    • 8.2.1 Star Ratings
    • 8.2.2 Detailed Star Rating Scores
    • 8.2.3 Key Safety Features of the Road
    • 8.2.4 Impact of Mitigation Measures and Investment Plan
    • 8.2.5 Impact of Individual Mitigation Measures
    • 8.3 Summary Findings
    9. Conclusion and Recommendations
    • 9.1 Conclusions
    • Literature review
    • Crash analysis
    • Road infrastructure as a motorcycle crash factor
    • Mitigation measures
    • Mitigation measures for prominent crash types
    • Stakeholder consultation
    • Review of Austroads Guides
    • Safety benefit analysis
    • 9.2 Recommendations
    ReferencesAppendix A AusRAP Star Rating Score (SRS) Risk Factors and Equation
    • A.1 Motorcycle Star Rating Score Equation
    • A.2 Risk Factors
    Appendix B Workshops and Consultations
    • B.1 Questionnaire Respondents
    • B.2 Responses to Questionnaire
    • B.3 Workshop Attendees
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