Nine To Noon Calculating the hidden costs of road crashes
Mar 18, 2026
Chris Blackmore, Head of transport modelling and economics at Abley, explains how crash costs are often vastly underestimated. He walks through how social costs are calculated and what current methods miss. He shows how richer traffic data reveals network-wide ripple effects, rerouting and extra travel that push real costs much higher.
AI Snips
Chapters
Transcript
Episode notes
Traditional Social Cost Framework For Crashes
- Road crash social costs traditionally estimate immediate healthcare, ACC and productivity losses around national value figures.
- Chris Blackmore explains these use top-down and bottom-up studies yielding figures like the updated NZ value of statistical life used for national costing.
Common Costing Misses Secondary Network Effects
- Immediate crash costs capture first responders, hospital admissions and some road-closure time but ignore many secondary network impacts.
- Chris Blackmore says existing methods use limited physical sensors and give only high-level closure estimates, missing downstream effects.
TomTom Data Reveals Networkwide Route Choices
- Newer TomTom data fuses sources like Apple, cell routing and in-car data to map travel times and route choices across the whole network in near real time.
- Blackmore says this dataset allows watching how drivers re-route, make U-turns, or use back streets, revealing broader congestion patterns.