Illustrations thanks to the talented Gabrielle Baker.
“We need to stop trading off health against transport emissions goals and put in place things that deliver on both of them. We can’t afford not to as a country.”
This is Dr Caroline Shaw’s message to policy-makers: we need to have policy solutions that address multiple issues. She is a public health doctor at the University of Otago. The health benefits of a low-carbon transport system have long been her field of study – and her passion.
Starting in 2020, she and her team began modelling the outcomes of the Climate Change Commission’s pathways to net zero. The Climate Change Commission is the government’s agency for evidence-based climate advice and monitoring our progress toward achieving low-emissions and climate-resilience goals. The Commission had advised the government on a number of pathways for New Zealand to achieve net zero for long-lived gas emissions by 2050.
Two pathways: same emissions, different futures
Dr Shaw’s team modelled the two most different pathways to see what their health, environmental, and climate impacts would be. One pathway predominantly relied on electric vehicles. The other one looked at a more mixed approach with much higher levels of cycling, walking and public transport.
“I was interested in electric cars because I didn’t agree with how the Climate Change Commission had thought that the electric car scenario would play out. There was a whole bunch of theory on what happens if you just move to an electric car fleet that suggested otherwise.
Meanwhile, she explains, many believe policies supporting a more diverse transport system with more active and public transport are nice-to-have. In other words, New Zealand could just elect not to do them. In contrast, people believe that electrifying the fleet is a solution that would work by itself.
“No one had explored the impact of what happens when you just move to an electric car fleet. I thought, this model will answer a bunch of those questions.”
It turns out we have decades of data we can use about what happens to people’s transport behaviour under a range of scenarios, such as a lower cost-per-kilometre when petrol prices drop. This data, along with many other sources, helped Dr Shaw’s team create a comprehensive model to see what transport behaviours would be like with an electrified fleet. A key difference in this scenario is the lower cost per kilometre compared to fossil fuel cars.
The surprising scale of the results
Even for Dr Shaw, who had expected to see an impact, the results were surprising.
“We found that people would drive more than they currently do if they get hold of cars that are significantly cheaper to drive per kilometre. And that number was really high. It was about 20% more overall.”
Why would people travel so much more? It’s because of the unmet desire to travel more. People who live in low-income neighbourhoods in this country drive around 100 kilometers less per week than people who live in high-income neighbourhoods. Most of that is because of money. We also know that from other evidence, for example, people not being able to afford trips to healthcare providers, etc.
“Lots of people are unable to travel as much as they would like to,” says Dr Shaw. “There’s a whole series of reasons for us to expect that if driving gets cheaper, people will drive more.”
Why is 20% more driving a problem?
A nationwide Vehicle Kilometres Travelled (VKT) increase of 20% is substantial. It increases congestion and all the problems associated with congestion, but also it increases risk of injury and risk of certain types of air pollution.
That’s because air pollution from driving comes not only from exhaust fumes from fossil fuel vehicles but also from non-exhaust sources like tyres and brake wear. These include the insidious “particulate pollutants”. Dr Shaw explained that there’s a growing body of research about the harm caused by particulate pollutants because, after we inhale them, they are small enough to cross into our bloodstream, causing all sorts of problems.
What would the future look like with more cycling, walking and public transport?
What about the other scenario that Dr Shaw’s team modelled, the one with more cycling, walking, and public transport? Dr Shaw found that it was a win-win-win scenario.
“What we showed in that work that we did is that you get the same kind of level of carbon benefits but the health benefits are really different between the two scenarios. They’re much greater in the scenario where we increase the amount of cycling, walking, and public transport use. We save lots of money and we don’t compromise our carbon goals.”
What are the policies which could help us?
Dr Shaw believes policies don’t have to be a compromise between health, good transport options and a fair society – we have all of them at once.
The key, in her view, is accounting for health harm from transport – something she says we treat as an inevitable by-product of wanting to move around.
“We already know that the current transport system is incredibly unhealthy and it’s killing at least as many people as smoking every year in this country. We’ve normalised all of the health harm from transport. But it actually doesn’t need to be inevitable.”
Different policy choices can reduce health harm from transport – and some of the gains can be realised quickly, Dr Shaw points out.
“For example, speed limit reductions are actually a really good policy in terms of reducing health harm quite quickly because we know that as soon as you put the speed limit reductions in place, the road injuries reduce. The converse happens as well: as soon as you put speed limits up, the health harm starts.”
Investment in active and public transport can also see returns quickly as behaviour can change physical activity and transport choices rapidly.
“Look at investment in cycleways here and internationally. A lot of them see immediate changes in cycling uptake and changes in physical activity. Rapid bus networks can be expanded quickly, as we’ve seen overseas.”
Choosing our path
Dr Shaw explains that while electric cars are ‘definitely in our future,’ we need to make informed decisions about how big a part of our transport system we want them to be. In her view, we should be aiming for them to be only a small part of urban transport systems. That’s partly because of climate-related weather events and the different urban systems needed to mitigate them, but also how we connect and live well together as a society.
“Our cities are becoming denser, and at the same time, we’re going to be seeing more intense rainfall because of climate change. Because of those factors, space should be reallocated to public spaces where people can have playgrounds, green spaces, water gardens for the rainfall that we’re going to be getting.
“Those things also make cities fun places for kids to live and for older people to socialise and so on. Most of all, those sorts of things will make our cities bearable under a changed climate.”
Many thanks to Dr Shaw for taking the time to share her research findings with Bike Auckland. We look forward to seeing more of her insights in future.
