Benchmarking temporary traffic management (TTM) against risk analysis and uncertainty characterisation literature: a documentary analysis of New Zealand’s TTM system

Temporary traffic management (TTM) is transitioning from prescriptive standards to risk-informed approaches in New Zealand and other jurisdictions. Whether practices adopted under the ‘risk-based’ label align with established risk analysis and uncertainty characterisation literature has not been evaluated. This study addresses that gap through a systems-level documentary analysis. Regulatory, guidance, training, procurement, and academic documents are coded across a five-stage decision cycle and mapped against two benchmarks: Paté-Cornell’s uncertainty treatment levels and Aven’s risk description framework (A′, C′, Q, K). The resulting maturity profile places New Zealand’s TTM system at Levels 1–2 across all five stages. Hazards are identified from generic lists, consequences described with fixed categories, no explicit uncertainty measure accompanies any stage, and background knowledge is disconnected from risk descriptions. The system uses the language of risk-informed decision-making without producing the risk descriptions the benchmarks require. Improvement requires explicit risk descriptions proportionate to site exposure, complexity, and consequence – not necessarily advanced probabilistic methods. The benchmarking method is replicable and can be applied by other jurisdictions to their own TTM systems.