Promoting active travel modes using agent-based modelling
Nick Bec
Active travel is often overlooked in decision making because it’s hard to quantify its impacts and benefits compared to large scale infrastructure schemes. That is where, explains Arup’s Nick Bec, transport simulation using agent-based models comes in…
Why are active modes important?
Active travel is a crucial part of how we get around. Short trips are dominated by walking, and many of our longer journeys involve active modes; we cycle to and from the train station or between bus stops to make a transfer. Walking and cycling is such an important part of how we travel that Active Travel England is aiming for 50% of trips in England’s towns and cities to be walked, wheeled, or cycled by 2030. Active modes offer low-cost, low-carbon alternatives to driving, and can provide numerous health benefits, in addition to improving the performance of the transport network.
However, active travel is often overlooked in decision making because it is hard to quantify its impacts and benefits compared to large scale infrastructure schemes which impact huge numbers of people. For active travel to be considered as part of the future transport mix, decision makers need to understand its full potential. To do this, we need to break down modal silos and show all of benefits active travel can create.
For active travel to be considered part of the future transport mix, decision makers need to understand its full potential
Simulations can show the benefits of active modes
This is where transport simulation, or agent-based models (ABMs) come in. ABMs are a way of simulating populations of virtual people (agents), and their transport choices as they try to complete a full day of activities. They can choose how to travel across private, public, and active modes of transport. They can also choose their routes and when they start their journeys. As these virtual people interact with one another and the transport network, we see complex responses and emergent behaviour across the system that are the same as those we see in the real world.
This ability to represent multi-modal trips and focus on people is what makes an ABM different from traditional models, and the level of detail lets us quantify the benefits of active travel investment. This also allows us to look at how different policies impact carbon emissions by calculating a profile for every vehicle based on transport mode, engine type (if applicable), speed, and distance for every trip in our simulation.
We can also look at how different groups of people are impacted – we tend to see that people on lower incomes benefit most from active travel, and that road tolls tend to be less effective at changing the behaviour of higher income people. Neither of these are necessarily revelations in transport policy, but our ability to easily quantify these impacts and look at how they interact with one another sets the simulation-based approach apart.
Our ability to easily quantify impacts and look at how they interact with one another sets the simulation-based approach apart
A better, more active, future for transport
A successful future for transport and mobility means we think about how people can best travel using various modes and combinations of modes. Simulations allow planners and decision makers to properly articulate the vital role of active travel as part of the wider transport system. If we succeed in this, active modes will come to play a bigger part in future transport policy, infrastructure, and investment. In turn, this will improve the performance of all modes and allow us to deliver more equitable, sustainable, and effective transport.
Arup’s City Modelling Lab
Over the last five years, we have invested in developing our ability to build and analyse these ABMs through our City Modelling Lab team. Since the Lab was founded, we have built large-scale models for cities, regions, and even whole countries globally. We collaborate extensively with academia and publish a large (and growing) proportion of the software that we develop under an open source licence. This helps increase the use of our tools and opens up our work to critique and wider contribution. It also makes the outputs of our work more transparent, which is very important if they are going to underpin policy decisions. We have a big focus on active travel in our models, but we are also tackling challenges around post-pandemic travel patterns, electric vehicles, and road user charging to help shape long term policy making.
Nick Bec is Arup’s City Modelling Lab Business Lead for Transport Consulting. An analytics professional with over 15 years of experience, with an academic background in maths, computer science, and operational research, Nick focuses on delivering cutting edge transport simulations that help clients answer their most pressing questions about modal shift, decarbonisation, and equity.
For further insight into Arup’s City Modelling Lab, please join Nick’s session at Google Prism stage on Wednesday, 19 April from 12.00 to 12.15. Interchange is free to attend, register now by clicking here