Study Warns of Unintended Trade-offs in NZ’s EV Transition

Climate advocates often promote electric vehicles (EVs) as a key solution to combat climate change. Unlike internal combustion engine (ICE) vehicles, EVs produce zero tailpipe emissions, reducing air pollution and helping to lower greenhouse gas emissions.

However, a recent study from Aotearoa New Zealand warns that focusing solely on switching from ICE vehicles to EVs—without considering driver behaviour or providing alternative mobility options—may lead to unintended trade-offs, particularly for public health.

Findings from the New Zealand study

Published on 30 June 2025 in the Journal of Epidemiology and Community Health, the study modelled how widespread EV adoption, without improvements in public transport or cycling infrastructure, could affect driving habits and health outcomes. It considered factors such as physical activity, air pollution, and the risk of road injuries.

The results suggest that a large-scale shift to EVs would reduce emissions and air pollution, but could also lead to more road injuries. Since EVs are cheaper to run than petrol or diesel cars, people are likely to drive more frequently, which increases their exposure to road accidents.

The research team, led by Dr Caroline Shaw of Otago University, concluded that the health and climate benefits of EVs could be maximised only when paired with broader measures such as fast and reliable bus networks, safe cycling lanes, and incentives for walking or e-biking.

Health and economic trade-offs

The study compared 2018 driving patterns with projections for 2050. It is estimated that by 2050, 75% of vehicles in New Zealand will be electric, but average driving distances per person will rise by 21%.

While reduced air pollution will deliver climate and health benefits, the increased time spent driving is projected to cause a net loss of 270 healthy life years, alongside an estimated NZ$44 million in added costs to the country’s health system.

The researchers suggested that distance-based charges could offset some of these adverse outcomes by discouraging excessive driving and helping to balance health and climate objectives.

A balanced path forward

The study underscores that while EVs play an essential role in reducing emissions, they are not a silver bullet. Without complementary investments in public transport, cycling, and walking infrastructure, New Zealand risks missing out on significant health gains.

Policymakers, the study concludes, should adopt a broader mobility strategy—one that combines EV adoption with systems that reduce car dependency and promote healthier, more sustainable travel options.

PHOTO CREDIT: Tesla at the Oamaru Harbour Precinct, Oamaru, New Zealand