Calibrating infrastructure risk rating (IRR) to inform speed management in Queensland

Infrastructure Risk Rating (IRR) is a road assessment methodology designed to assess road safety risk, primarily as an input to the speed management process. It is one of the attributes underpinning the framework in NZ Transport Agency’s Speed Management Guide and has been applied nationwide in New Zealand. As part of reviewing their speed management guidelines, the Department of Transport and Main Roads were keen to test IRR on Queensland roads. This paper presents the results of applying IRR on various road environments in Queensland with the aim of developing a single IRR model that is calibrated for all roads.