Thanks to Kenn Beer, Principal Engineer at Safe System Solutions for this article published on LinkedIn.

Road Safety Audits (RSAs) have long played an important role in identifying design issues that may lead to crashes or make crashes more serious. But audits alone often lack a consistent way to measure risk or communicate the scale of safety improvements.

In 2022, Safe System Solutions Pty Ltd worked with iRAP and the Asian Development Bank (ADB) to develop a process that makes Road Safety Audits (RSAs) more objective, and encourages more ambitious, Safe System-aligned recommendations. Enter our new process: Star Ratings for Road Safety Audit (SR4RSA).

SR4RSA merges the strengths of RSAs with iRAP’s internationally recognised Star Rating methodology. It gives decision-makers a more reliable, repeatable, and quantifiable way to assess and improve safety performance during the design phase. And best of all – the guide on how to do this is freely available.

Why It Matters

RSAs are expert-driven and context-sensitive, but often subjective. iRAP’s Star Ratings are data-driven and standardised but may miss local nuances. SR4RSA combines both approaches to:

• Quantify safety risk using a 1–5 star scale for all road users
• Provide evidence to support design recommendations
• Align with global targets (e.g. all new roads achieving 3 stars or better)
• Estimate crash reductions and economic returns

It’s a neat way of making the Safe System approach real and measurable.

How It Works

SR4RSA can be applied at different levels depending on project size, stage, and available data:

• Level 1: Rapid assessments of individual audit findings using the iRAP Star Rating Demonstrator
• Level 2: Star Ratings for full design lengths, before and after applying audit recommendations
• Level 3: Corridor-wide analysis with Star Ratings, fatality estimates, and cost–benefit analysis using iRAP’s SR4D platform

Each approach helps road agencies better understand the impact of design changes on safety.

When to Use SR4RSA

SR4RSA fits naturally into the concept, draft, and detailed design stages, and is also valuable at pre-opening. It ensures that recommendations are tied to measurable safety outcomes and helps confirm that performance targets (like 3-star minimums) are being met.

Global Alignment and Impact

SR4RSA supports the UN Global Plan for Road Safety, including:

• Target 3: All new roads to be 3-star or better
• Target 4: 75% of travel on 3-star roads or better

It’s also highly cost-effective. Research shows Star Rating upgrades can prevent thousands of deaths by smarter infrastructure decision making, that doesn’t cost much (if any) more in a project.