Road safety risk assessment

Before you can deliver effective road safety interventions you must understand road safety risk across your network. We take the heavy lifting out of road risk assessment, so you can focus on planning and implementation. 

Our work has helped reduce fatalities and serious injuries on the roads in New Zealand, Australia and around the world. We can help you with all your road safety challenges.

Our methods are founded on Safe Systems principles. We can support you with strategy development, speed management, infrastructure programmes, protecting vulnerable road users and enforcement. 

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Start with network risk analysis

The first step in developing your infrastructure and speed management programmes is understanding the relative safety of intersections and corridors across your road network.

You can assess network risk in many ways, including:

  • Predictive methods that identify the underlying risk of road elements, such as Infrastructure Risk Rating and high-risk curve analysis (more on these methods below).
  • Enhanced crash analysis methods that apply severity indices to injury crashes to predict the likelihood of future deaths and serious injuries.
  • Crash movement analysis, e.g. run-off road crashes in rural areas.
  • Road user analysis, e.g. focusing on vulnerable road users such as pedestrians, cyclists, and motorcyclists.
  • Assessing intersection risk using a combination of historic crash data, crash severity indices, intersection form and operating speed.

We are the preferred supplier of network-level high risk road and intersection assessment for road agencies in New Zealand and Australia. If you need to understand risk across your road network, we can help.

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Assess your infrastructure risk

Infrastructure Risk Rating or IRR is a method for assessing road risk based on land use, road design and operational characteristics. It is based on the Star Rating approach but uses existing road asset and operation datasets – so you don’t incur the expense of collecting additional road survey data.

Your network’s IRR score is a proven predictor of actual safety performance and risk to road users. This means IRR can be used to justify interventions ahead of safety issues manifesting as crashes.

IRR can also be used to inform the development of your safety strategies, infrastructure, and speed management programmes.

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speed management

Identify your high-risk curves

More than half of all fatal and serious crashes on high-speed roads occur on horizontal curves.

We can assess the risk of curves independent of historic crash data, using curve approach speed and curve radii. This method is particularly useful for low volume rural roads, where crashes tend to be sporadic and random.

Our modelling approach identifies curves that are out-of-context for the approach speed, radii, and direction of travel. Curves are then assessed at a corridor-level. This helps you prioritise roads with high-risk curves, using strategies like mass action curve treatments and speed management.

Our curve analysis can also identify safe advisory speeds, including the style and location of warning advisory signs.

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speed camera

Make your enforcement more effective

Enforcement programmes aim to improve driving behaviour by discouraging poor driving behaviours, such as speeding, drink driving and driver distraction. Enforcement is more effective when targeted at locations and times where there is the greatest risk of serious crashes.

Using advanced crash analytics, we provide road authorities and Police departments with evidence to justify road safety enforcement investment.

Our techniques have been applied in New Zealand and Australia to identify optimal sites for speed and red-light cameras, and to prioritise funding for targeted speed and drink driving enforcement.

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Address high-risk crash locations

Scope targeted solutions and deliver quick wins at high-risk crash locations with crash commonality analysis.

Understand common factors in crashes at high-risk intersections and corridors without onerous manual assessment of individual crash reports.

We analyse movement codes, road user involvement, temporal and environment factors to identify factors well above typical proportions and propose effective solutions.

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International Road Assessment Program (iRAP)

iRAP is the global programme for Road Assessment Programmes (RAPs). More than 100 countries use iRAP for risk mapping, Star Rating and safety investment planning.

iRAP’s Star Rating tools use road video data to assess the risk of major roads. The Star Rating reflects the relative risk of the road for vehicle users, pedestrians, cyclists, and motorcyclists. iRAP’s VIDA analysis tool uses the Star Rating data to generate a prioritised Safe Roads Infrastructure Program.

Other tools developed by iRAP include:

  • Star Rating for Designs assesses the safety of new road designs.
  • Star Ratings for Schools assesses safety around schools.
  • Star Ratings Demonstrator assesses the safety of sections of existing road.

Shane Turner is Abley’s accredited iRAP supplier – contact him to learn more about how iRAP can assist you with your safety problem.

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road median barrier

Safe System framework assessments

Evaluate the extent to which your existing or proposed road infrastructure aligns with Safe System principles, identify your key safety deficiencies and determine how different upgrade options would address these deficiencies.

These assessments produce a score based on the number of road users, design characteristics and expected crash severity using a methodology developed by Austroads. 

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Protect vulnerable road users

Proactively assess risks to vulnerable road users – pedestrians, cyclists, motorcyclists, and micro-mobility users – with Urban Safe System Assessments and Multi-User Safety Assessments.

Urban Safe System Assessments evaluate the risk of specific crash and road user types, considering exposure, likelihood and severity for each intersection and midblock subdivision.

Multi-User Safety Assessments apply a safety audit-style approach to identify and rate sites and sections that have increased crash risk for vulnerable road users. We focus on the most vulnerable: the elderly, young and disabled.

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Level crossing safety

Level Crossing Safety Impact Assessments (LCSIA) were developed by KiwiRail to understand risk at existing and modified level crossings.

Any safety audit that incorporates a level crossing is subject to an LCSIA. Any new designs or modifications to rail crossings must also be assessed and reviewed by a KiwiRail-accredited reviewer.

Shane Turner is a New Zealand expert on LCSIA. He worked with KiwiRail to develop the LCSIA methodology, is a KiwiRail accreditation trainer and continues to advise KiwiRail on level crossing safety. Contact Shane if you need your level crossing safety audit reviewed.

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Crash prediction tools for complex environments

Crash prediction tools evaluate risk using a combination of crash prediction models or safety performance functions, crash reduction factors and crash severity factors.

For more complicated layouts, the Extended Kinetic Energy Management Model (X‑KEMM‑X) assesses the transfer of kinetic energy between conflicting road users based on collision angle, speed and vehicle mass. 

In addition to assessing risk, these tools can calculate predicted crash costs for economic appraisal.

My team has engaged Abley extensively over many years … The most recent work has been the delivery of the Speed Management Framework and associated mapping tool, which has not only received praise from road controlling authorities across New Zealand, but has also been the basis of recognition at international conferences and has been adopted wholly or in part by Australian states.”

Glenn Bunting, Manager Network Safety, Waka Kotahi NZ Transport Agency

Case study

Helping Waka Kotahi NZ Transport Agency to save lives on our roads

One of the first large pieces of work we did with the Agency was developing SafetyNET. This project mapped risk across the state highway network using both proactive and reactive risk metrics. This was used by Waka Kotahi to identify locations needing road safety improvements.

Contact our road safety experts

Paul Durdin
Director, Transport

Shane Turner
Technical Director, Road Safety