The Laws of Physics, Modelling & Future Transport Scenarios

In our February eNews, we met Andy Ford, Manager of the Wellington Transport Analytics Unit (WTAU), to learn about the work they do.

This month, we meet Christoph Gerds, Team Leader at WTAU, and learn about the laws of Physics, Modelling & Future Scenarios. Specifically, Christoph shares a brief overview of a couple of projects that WTAU have worked on with the Wellington Regional Leadership committee – the FDS and WTERP. For those not up to date with their acronyms:

  • FDS = Future Development Strategy, the process of developing an agreed strategy for how and where the region can accommodate the up to 200,000 people who might call the region home over the next 30 years 
  • WTERP – Wellington Transport Emissions Reduction Pathway, which outlines pathways for the region to achieve a 25% drop in per capita VKT and transport emissions by 2035.

Q Before we talk about transport, maybe a few words about yourself. What’s your background? 
A Sure, I was born and raised in northern Germany, near the harbour city of Kiel. That’s also where I studied Physics. After that, I spent some time in India and then in Norway and eventually ended up in Wellington back in 2007. 

Q Physics, hm… So how did you end up in transport modelling?  
A The difference is not as big as you might think. In physics and in transport modelling you try to describe the world using mathematical models. Of course, that means lots of computers and programming.  

Q And what would you like to talk about today? 
A I’d like to give you an overview of some work we have done for the FDS and WTERP. 

A Almost! So, the FDS is the Future Development Strategy, the process of developing an agreed strategy for how and where the region can accommodate the up to 200,000 people who might call the region home over the next 30 years. And the WTERP is the Wellington Transport Emissions Reduction Pathway, which outlines pathways to meet our climate goals.  

Q OK, so what is the work you have done for these? 
A We have looked at a number of different future scenarios. That means different assumptions as to where people live and work and what the transport system might be. For that, we have used our big transport model that’s called the Wellington Transport Strategy Model. Or short, WTSM. 

Q What were those scenarios, and what have you found out? 
A For the FDS, we have looked further into the future, where we expect the quite a few more people to live in the region. Our scenarios model a future that is about 30 years away. We expect about an additional 200,000 people will live in the region then. And one of the big questions is where exactly will they live, and also how will they get around? 

Q And for that you can use your model? 
A Partly… The model can’t tell us where people will live, or what the transport network will look like in 30 years time. What the model can help with is to say: Assuming this is how the network looks like, and assuming where people will live, what does that mean for how they’ll likely get around. 

Q That’s a lot of assumptions… 
A True, but these are also the things we can influence. I mean, not me necessarily, but politicians, the WRLC and so on. 

Q and what about the other project you mentioned, the WTERP? 
A Yes, so for the Wellington Transport Emissions Reduction Pathway we have looked into how the transport system has to change so that we meet our climate goals. For most of this, we have looked at a shorter time frame, more like 10 years, out to 2035. With this shorter time, we don’t expect so much population growth or change in the urban form.  

Not saying that that is not important, it’s hugely important to set the right course now.  

But, with not much chance to fundamentally change the urban form within 10 years, the question is what can we do? One obvious answer that people often jump to is electric cars, but again, over 10 years that will fall way short of where we’ll have to be. Essentially that means we’ll have to make up the shortfall with driving less.  

Q How much less?  
A Within the WTERP the aim is for a 25% reduction in VKT per capita, that is Vehicle Kilometre Travelled. So basically, we’ll have to reduce the distances we drive daily by 1/4. That is on average, of course. For some people it might be more, for some less, and some might even drive more then today. But an average 25% reduction in VKT is a huge goal. 

Q So, how do you model that? 
A Basically, we pushed the model to it’s limits, and then some. What I mean is, we have taken every lever that is commonly used in the model and pulled it as hard as plausibly possible. For instance, in theory we could have put in a bullet train from Masterton to Wellington, but that’s not plausible. So instead, we have put in improvements in rail-frequency that are ambitious, but realistic. 

Q Anything else? 

A Oh yeah, heaps more: Bus lanes and more buses throughout the region, improvements for active modes like cycle lanes on steroids, also 30km/h speed limits in all residential areas and centres, parking management, Traffic Circulation Plans… 

Q What are those? 
A The idea of a traffic circulation plan is that you disable through-traffic from an area by strategically blocking off certain connections for cars. You can still drive to most places, but it becomes a lot more convenient not to drive. 

Q Speed restrictions, blocking off cars… don’t people hate that? 
A The funny thing is, once in place, and done well, the experience shows most people really, really like it.  

Q OK, so you put all these things into the model and then we meet the climate targets? 
A No. 

Q No? 
A No, we put all this in, and we are still short. So, we also put in some additional pricing mechanisms, road pricing, congestion charging, time of day pricing, something like that. We have modelled a specific version of course, but that’s not set in stone. 

Actually, that is another thing I’d like to mention, the model won’t tell us everything, but it can give us a good sense of the direction and of the magnitude of change required. 

Q But people surely hate the pricing? 
A Only to some degree, if they can see the benefits it brings, most folks seem to be OK with it. Also, economists love it. So, that makes it palatable to both sides of the political spectrum, which is always a bonus. But it is really important that road-user pricing must be accompanied by affordable, reliable and safe alternative modes, so that’s improvements in public and active transport. Without viable alternatives to switch to, it risks being seen just as another tax, and an anti-car penalty, that few people would support. 

This is also a general rule here, the WTERP really highlights how important it is to take actions as a suite of interventions, not in isolation. 

Q Any final words? 
A Perhaps just that the future we’ve modelled for the WTERP not only helps meeting out climate targets, but by giving people choices it’s also a healthier and a cheaper future than one where people are more reliant on their cars to get around. 

Follow the work of WTAU here.

Wellington Regional Leadership Committee

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