Research shows lower speed limits won’t significantly impact vehicle emissions Research shows lower speed limits won’t significantly impact vehicle emissions

Date: 19 May 2023

It’s Road Safety Week this week and Auckland Transport (AT) has released new independent research that looks at the impact of lower speed limits on vehicle emissions.

The research concluded that although changes in vehicle speed can affect emissions, the overall impact of lower speed limits on emissions in Auckland will be negligible.

The research report was prepared by Emission Impossible Limited, an independent consultancy specialising in air quality and vehicle emissions management.

Jayne Metcalfe, Director at Emission Impossible, says "we know that speed can affect vehicle emissions, but our research has found that the overall impact of speed limit reductions on greenhouse gas emissions and air pollution from vehicles in Auckland will be small.”

Ping Sim, Auckland Transport’s Safety Lead, says AT is continuing to develop safe and appropriate speed limits under a new draft speed management plan – Katoa, Ka Ora.

She says it is reassuring to see this research as AT works to reduce the impact of vehicle emissions in Auckland, alongside setting safe speed limits.

“We’ve heard from Aucklanders that one of their concerns around lowering speed limits is whether it would impact vehicle emissions.

“Safe speed limits and emissions reduction goes hand in hand for us at Auckland Transport. Evidence shows that we need to reduce reliance on cars and support people to walk, cycle and use public transport. Safe speeds, which makes it safer to walk and cycle, will therefore also be a critical part of the emission reduction pathway for Auckland and New Zealand.”

Ping says the upcoming speed management plan for Auckland, Katoa Ka Ora, will be vital if we want to work towards a New Zealand where no one is killed or seriously injured in road crashes.

“Speed is one of the main determinants of whether anyone is killed, injured, or walks away unharmed from a crash. This makes speed management critical to saving lives in Auckland. We want to ensure everyone gets home safely to their loved ones every day.”