Safe roads calculator

The Infrastructure Risk Rating (IRR) calculator is a free resource provided by Abley, based on the Waka Kotahi NZ Transport Agency’s Infrastructure Risk Rating manual (read more). To use the calculator, enter values for all of the inputs below and click Calculate.

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Please enter a value greater than zero.
Please enter a whole number greater than zero.
Please enter a whole, non-negative number.

How is this calculated?

Infrastructure Risk Rating (IRR) is a method for assessing road risk based on land use, road design and operational characteristics. A road’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.

At Abley, our road safety teams are proven experts in assessing risk on road networks throughout New Zealand and overseas. Visit our road safety page to learn more.

More information

For more information about IRR, including definitions for the tool inputs, please see the Waka Kotahi NZ Transport Agency Infrastructure Risk Rating manual.