Baseline Research Program: Addressing Outer Urban Road Safety in Metropolitan Melbourne: Final Report

Introduction and Aims
The purpose of this MUARC baseline project was to identify road safety issues specific to Outer Urban Areas (OUAs) of Melbourne, and to provide recommendations and estimated benefits of proposed strategies for addressing high priority areas. To achieve this aim the project was divided into 5 complementary phases.
• Phase 1: Identification and collection of available data sources
• Phase 2: Definition of outer urban areas
• Phase 3: Analytical tasks
• Phase 4: Identification of previous and current investment
• Phase 5: Identification of solutions to address problems
Phase 1: Identification and collection of available data sources
To develop an up-to-date definition of outer urban areas of Melbourne relevant to the project aims (Phase 2), we used an accessibility/remoteness index (ARIA+(2006)) combined with supplementary measures of population growth, growth in home ownership, number of businesses, and the registered vehicle fleet. The descriptive analysis (Phase 3 Part I) utilised Victorian police reported crash data (2008-2012). The logistic regression analyses (Phase 3 Part II) utilised Victorian Police reported crash data (2000-2013), with added market group data for crashed vehicles.
Phase 2: Definition of outer urban areas (OUAs)
A modified version of the accessibility/remoteness index (ARIA+ (2006) was proposed to define outer areas of Melbourne as well as inner urban Melbourne and regional areas of Victoria for the purpose of comparative analyses (Phase 3). Six Local Government Areas (LGAs) were identified as outer urban areas of Melbourne: Cardinia, Casey, Hume, Melton, Whittlesea and Wyndham.
Phase 3: Analytical tasks
The analysis was conducted in 2 parts. In Part I, a descriptive analysis identified a fatality rate more than two times higher and a serious injury crash rate 40% higher for outer urban areas, when compared to inner urban Melbourne. Results of the descriptive analysis also included a much higher average speed zone for fatal and serious injury (FSI) crashes in outer urban areas (75 km/h cf. 63 km/h), a higher proportion of crashes involved younger adults (10-21yrs), and a lower proportion involving older drivers (70+ yrs) for outer urban areas.
In Part II of the analysis, a logistic regression with three separate models (crash-based, driver/vehicle-based, and road user-based) was used to identify factors significantly over or under-represented in outer urban areas compared to inner urban Melbourne. Factors identified as significantly over-represented FSI crashes in outer urban areas included: higher speed zones (especially on main roads), local roads, intersection crashes involving vehicles from the same, adjacent and opposite directions, large SUVs or utilities driven by males, and small vehicles driven by females.
Phase 4: Identification of previous and current investment and prediction of changes
Those factors found to be significantly over-represented in Outer Urban Areas (Phase 3) were ranked by priority, by adding crash prevalence data for OUAs. A desktop review on current road safety strategies and action plans at the National, Victorian and LGA levels, was conducted to determine
whether these priority areas for outer urban areas were being currently targeted. Based on the findings of high priority areas (Phase 3) and review of how well these are being addressed by current road safety strategies (Phase 4), the following five key priority areas were recommended:
• Increased focus and investment in Local Roads infrastructure
• Increased priority on Speed-related interventions
• Intersection treatments (adjacent/same direction crashes): signalised intersections/ roundabouts
• Promote uptake of safer vehicles
• Expanded program of Barrier treatments (runoff road and head-on crashes)
Phase 5: Identification of solutions to address problems
In the final phase, the eMETS modelling technique was used to estimate the benefits of three initiatives proposed for the outer urban LGAs. Based on the list of recommended road safety focus areas identified in Phase 4, three programs aimed at reducing serious casualties (S.C.) over the long term in outer urban Melbourne were investigated conceptually. These were:
• Speed zone changes in current 80 km/h and 100 km/h speed zones
• Intersection improvements; and
• Reduction in the average age of the vehicle fleet
Speed zone changes
For changes to current 80 km/h zones, a 10 km/h speed limit change in all current 80 km/h speed zones is estimated to lead to an annual reduction of between 10 and 50 serious casualties (including 4 fewer fatalities), based on a conservative 3 km/h reduction in average travel speed, and between 15 and 75 serious casualties (including 6 fewer fatalities) based on a 5 km/h reduction in average travel speed. For 100 km/h speed zones, a 10 km/h speed limit change in all current 100 km/h speed zones is estimated to lead to an annual reduction of between 10 and 35 serious casualties (including 4 fewer fatalities), based on a conservative 3 km/h reduction in average travel speed, and between 10 and 50 serious casualties (including 6 fewer fatalities) based on a 5 km/h reduction in average travel speed.
Intersection improvements
The top 19 intersections in outer urban areas were identified, based on recording more than six serious casualties over the period 2008-2013. Three have since been converted to roundabouts and one has received significant upgrades, leaving 15 in the analysis. Measures such as local intersection speed limits, speed/red light cameras, cut-through or ‘squircle’ intersections, signalised and non-signalised roundabouts were considered. Overall, a target serious casualty reduction of 40% was chosen representing the average effectiveness of a mix intersection treatments across the sites. When applied for these sites, these measures would likely result in reductions of 8-11 serious casualties per annum.
Reduction in the average age of the vehicle fleet
A theoretical analysis of the benefits of a younger vehicle fleet was carried out using the latest Used Car Safety Ratings (Newstead et al, 2016) to estimate the benefits had the vehicle in which the seriously injured or killed occupants were travelling been three, five or ten years newer. The analysis included crashes involving passenger and light commercial vehicles (utilities and vans) manufactured between 1974 and 2013 with a valid used car safety rating. Overall, it was estimated that a projected reduction in the average age of the vehicle fleet by 3, 5 and 10 years would lead to annual reductions by 76, 123 and 215 serious casualties (serious injuries or fatalities), respectively.