A University of Auckland lecturer says crash delays cost Auckland billions, not just lives.

Tim Welch, a senior lecturer in the School of Architecture and Design, says Auckland recorded 34,628 reported crashes between 2022 and 2025, and the real economic bill goes well beyond injuries, deaths, and emergency response.

A new analysis puts Auckland’s crash costs at NZ$9.23 billion over three years, about 2% of the region’s NZ$157 billion economy.

Welch says nearly NZ$200 million of that never really enters the public debate because it sits in a category most people overlook: network disruption.

NZTA’s official crash-cost method covers medical costs, lost productivity, property damage, and the statistical value of a life.

One fatal crash is costed at NZ$15.2 million.

But Flow Transportation Specialists, working for Auckland Transport, estimated how crashes trigger wider congestion using GPS travel-time data and traffic counts.

The analysis found a multi-vehicle motorway crash can generate NZ$1.4 million to NZ$3.5 million in network delay costs, while a serious arterial crash can cost NZ$26,000 to NZ$37,000 in lost time across affected road users.

Applied across Auckland, network delays add about NZ$195 million, a 2.2% lift on conventional estimates.

Welch argues this matters as the Government rolls back earlier speed reductions, because claimed time savings ignore the time lost when higher speeds increase crash frequency and severity.

He notes the delay estimates are conservative and likely understate the true disruption.

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