Choose a number

May 3, 2021

Choose a number

Waka Kotahi NZTA was accused of ‘junk maths’ following its claims that a reduced speed limit on the Napier-Taupo highway would slow travellers by just one minute.

NZTA defended the claim as the accurate difference between two vehicles: one travelling at the current mean speed (81 km/h) and the other at the proposed limit (80 km/h).

Although the NZTA numbers are technically possible, drivers say they don’t take into account actual behaviour; that if you can’t travel the speed limit now due to traffic volume, you won’t be able to travel at the lower speed limit either. This is the challenge of using numbers or calculations in your messages: you can’t cherry-pick. They must be believable.