“Prediction is very difficult, especially if it’s about the future”


In this second post about the work of the Commission on Travel Demand I will explore the challenges posed by the quote from the scientist Nils Bohr that headlines this article.

Lets start by looking at the state of practice in the UK. All major infrastructure schemes are subject to an economic appraisal with an appraisal period of 60 years (which is 30 years longer than it used to be a decade ago). We produce long term estimates of demand using the National Trip End Model and a suite of other tools such as the National Transport Model and the Passenger Demand Forecasting Handbook. However, the demand futures upon which decisions are based are largely determined by what are deemed to be ‘reasonable assumptions’. The case for HS2 for example includes the following acknowledgment: “Despite the economic downturn there is little evidence to suggest the recent strong growth in long…

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Freedom of movement and fairness

Transforming transport planning for social and environmental justice

A new think-piece by Dr Caroline Mullen is one of two outputs on energy and mobility justice, written by members of the DEMAND Centre for Friends of the Earth’s Big Ideas Project.


Mobility and movement of resources is life sustaining and enhancing. Yet transport and mobility systems in countries across the world present a complex tangle of freedoms, benefits, health problems, physical dangers and restrictions. This think-piece argues that we should reframe thinking about transport so that equality – recognition that each and every person matters – becomes the starting point. Transport planning would then aim to ensure that each person can obtain the benefits of mobility, and to minimise social and health inequalities caused by transport. These premises would help us reconcile what can seem to be conflicting social and environmental goals. Practically this would mean treating transport as a matter of social and environmental justice, and thus making it a priority to ensure that people can move freely on foot, bicycle, and wheelchair, coupled with comprehensive, accessible public transport operated as a public good. This approach contrasts starkly with existing mobility systems that prioritise motor traffic and aviation. These existing systems create huge problems for human wellbeing, ironically restricting freedom for many people to move around safely and to participate in society, while damaging economic welfare, and causing serious harm to other species and the natural environment. Reframing transport as a justice issue also challenges existing political discourses and assessment tools, which have tended to encourage systems with heavy reliance on motorised transport and aviation, and which act as a barrier to a just transport system. The think-piece explores how a move to a just mobility system can draw broad political and public support by promoting multiple social, economic and individual interests. It outlines new methods of assessment and public participation in decision-making which could support a transition toward a more just transport system.

Read the full document here.

Why we should worry about travel demand


Today marks the launch of a new Commission on Travel Demand which I am chairing. This is the first in a series of blog posts where I will explore the thinking behind the Commission and share insights from events, evidence and public meetings the Commission hosts during 2017.

I start by looking at why we should be interested in travel demand. There are certainly greater short run policy priorities out there such as job creation and promoting productivity and competitiveness in a post-Brexit world. In fact, talking about demand can be politically quite challenging as the idea of limiting growth in demand or managing demand in particular places or times of day can be contentious.

However, I would argue that we are in a period of significant change and uncertainty where there are numerous opportunities to shape the course of the future growth in travel demand. Many of these influences…

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NORTHMOST – mathematical modelling in transport

NORTHMOST is a new biannual series of meetings on the topic of mathematical modelling in transport.

Held in December 2016, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.  The presentations are provided below.

The focus of the meetings will alternate; NORTHMOST 02 – planned for Spring 2017 – will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.

For further details please contact Dr Richard Connors

VirtuoCITY – a centre for city simulation


Cities are entering a new age where new technologies could dramatically change the way people move. New insight is required to understand how we will react to these new mobility options. The University of Leeds is developing a new centre, focused on engaging with the public to co-design and demonstrate new mobility options, and to gather feedback and build interest and user-acceptance.

Virtuocity will be a proving ground and accelerator in which emerging technologies are harnessed to develop innovative solutions to challenges facing cities.

Computational transport modelling has been around since the first general purpose computers were developed over 50 years ago. Early models focused on steady-state conditions. With the evolution of processing power, the models have become more detailed and accurate. Modern agent-based transport models capture each pedestrian and each vehicle and validate with data collected in existing cities.


Virtuocity will use these advanced models along with models of future technology to answer questions like: What should mobility in the city of the future look like? What does technology provide? What will users choose, accept and pay for? What does the resulting city look like? Local authorities wish to design their city to encourage healthy lifestyles, have a vibrant downtown and reasonable transit times. Automotive companies and mobility-as-a-service providers are seeking to understand how to design their products to maximise revenues and profits. The only way to answer these questions is with impactful end-user focused co-production and public engagement.

The University has an extensive set of research experience: experiments, data, models and simulations of cities from across the disciplines of social sciences, engineering and medicine. Virtuocity will combine these, so that any researcher can use them in their investigations. Corporate and public partners can also integrate their software, simulations, data and models thereby maximising the research capability of Virtuocity.

Virtuocity will:

  • Work collaboratively with end-users, industry partners and decision makers to answer pressing questions and co-produce new solutions;
  • Bring together a commanding set of shared data and models;
  • Encourage and support safe, efficient and sustainable mobility;
  • Explain and demonstrate new and emerging mobility options
  • Focus on the end-users and gather feedback on user acceptance, interest and choices.

Virtuocity will provide partners with a competitive edge through access to a unique combination of facilities, world leading research and key academic experts.

Corporate Partners
Virtuocity will provide corporate partners with a powerful company resource with members able to enjoy varying degrees of access, benefits and involvement dependent on their needs.

As a manufacturer or technology developer, you will have the opportunity to demonstrate and test your latest systems. Virtuocity will engage your end user in technology/system development by collecting critical feedback on preferences, usability, demand and safety.

As a consultancy or software developer, you will have the opportunity to leverage your own capabilities and software with those of Virtuocity. Bring your clients and customers in to experience Virtuocity technology integrated with your own software and assist them in making the right decisions about future cities.

  • Use of software, data, models, simulations, virtual reality hardware and simulators;
  • Priority access to University researchers, with expertise in a wide variety of fields;
  • The opportunity to place a researcher within the Centre;
  • Preferential access to reports, papers and research outputs;
  • Influence over the Centre’s future research roadmap through a seat on the Advisory Board;
  • The opportunity to contribute and formally link to active projects;
  • Access to joint research funding via collaborative bids;
  • Training opportunities.



Public Partners
As a local, regional, or national Government partner, you will appreciate the opportunity for positive change to be realised from modern mobility technologies. With Virtuocity, you can find out how to encourage your citizens to make healthy choices for mobility, what will make citizens spend more time in the city centres to stimulate vibrant economic centres, and how to reduce traffic jams, congestion, and parking demands. Virtuocity will help you to design cities that are more resilient to floods while reducing air and noise pollution. Citizens and decision-makers will be able to experience and provide feedback on alternative city project designs, before they are built through the use of virtual and augmented reality evaluations from various points of view – ranging from the city planner through service providers to the most vulnerable road users. Designs can be assessed with respect to safety, throughput, efficiency and cost.


Virtuocity will bring together industry expertise, public sector decision makers and academic excellence in a shared collaborative research centre to design the cities of the future. It will offer:

  • A world leading combination of facilities and researchers in a complex, dynamic and multi-disciplinary environment;
  • A coordinated and integrated approach to research to provide insight into the future of cities;
  • Vast experience in using technology to generate reliable and robust outcomes;
  • Interactive research and demonstrations and a proving ground for the co-production of data vital for an evidence based approach to innovation;
  • Collaboration opportunities to achieve better, more cost effective mobility solutions.

To find out more about how your organisation can take advantage of a membership please contact:

Dr Erik Thomasson
Research and Innovation Manager
Email: e.n.thomasson@leeds.ac.uk

Electric vehicles and renewable energy – what are the key issues?

Power grids need to accommodate an increasing renewable generation share, which adds the variability of the weather and climate systems to the electricity distribution network. Further uncertainty on the demand side will be introduced by widespread EVs’ recharging. Transport has been traditionally separate from the electricity grid but the transition to e-mobility will realize a closer integration. New configurations must be found to successfully merge renewable generation, electricity demand, transport/charging habits, and energy storage.


Will EVs be used as grid storage? The case of commuting
Car commuting is comparable to residential electricity usage in terms of societal and environmental relevance. Electricity storage may become the future replacement of “peak-following power plants”, currently turned on when electricity demand is high, and storage may be partly provided by batteries on board future EVs. Whether EVs will bring stability to the energy system or not, it is not straightforward to determine: the main point at stake is the effectiveness of plugged-in vehicles to supplement the electric grid in satisfying demand’s peaks and troughs. Another relevant aspect is the financial viability of using EVs’ batteries for purposes other than traveling, which increases wear and tear. EVs’ maker Tesla recently introduced a lithium-ion battery for residential usage, with technology and cost per unit capacity similar to EVs’ batteries; the divide between the two kinds of applications (cheaper, lower-tech packs for building use with respect to electric cars) may therefore get progressively blurred, thanks to technological advance and scale economy.

When and where will commuters charge their EVs?
It is often assumed EVs’ batteries will be recharged in the dead of night and early morning, when demand is lower than average, to then provide peak power when people wake up. Then, EVs are driven to workplaces by commuters and parked for the day. There, they can be topped up while the sun is shining, driven back home where they provide for the dinner-time peak demand, to start being recharged again late at night. Daytime recharging seems compatible with California power demand (Fig. 1, green curve): topping EVs up during office hours may flatten the “duckshaped” curve and accommodate solar generation. On the other hand, daily UK demand (Fig. 1, blue and red curves) does not display California’s afternoon trough: recharging millions of EVs parked in workplaces’ lots might therefore require additional peak generation rather than providing an outlet to excess power.

Variability in renewable generation and commuting patterns
During daylight hours (Fig. 2) in California, homes with solar panels cover a significant fraction of their own power needs, causing the demand trough displayed by the green curve in Fig. 1. This scenario may be unrealistic for the UK for two reasons. First, overcast skies suppress direct solar radiation, thus cutting up to 85% of clear-sky generation: the “duck” will exist only or mainly in sunny days. Second, the strong generation imbalance from winter to summer [1] due to high latitude can prevent the duck’s trough from occurring in autumn and winter, even with clear-sky conditions.

Each renewable generation mode shows its own peculiar variability and uncertainty pattern on different time scales (from hourly to yearly and beyond) and spatial scales [2], just as car commuting does (e.g., working days vs weekends). A fraction of variability is deterministic (entirely predictable, like the sun’s day-night cycle), whilst another fraction displays various degrees of unpredictability, depending on desired time advance and precision on location (an example being the effect of clouds on photovoltaic generation). With power supply limited to fossil fuel and nuclear power, climate and weather mainly influence the demand side of the energy market. Inclusion of renewables in the mix introduces a “double dependency” on weather/climate which can sometimes damp fluctuations (e.g., summer highs of solar generation in Texas satisfy the increased air conditioning usage) but often amplify them (reduced winter solar generation is coupled with higher heating and lighting needs). Adding EVs to the balance makes the problem even more complicated. For example, bad weather can affect car usage patterns; likewise, heating the cabin of an EV on a winter day increases consumption.

Coping with variability and unpredictability
EVs maximally help the grid if they are plugged-in, with the appropriate charge level, when generation or demand peaks occur. The seasonal imbalance may however cause the future British renewable mix to include a solar share smaller than sunnier countries; alternatively, long-term storage (like using electricity to produce hydrogen) will be the way to carry summer excess energy to the following winter. In either case, the grid may not need EVs’ batteries plugged in at around midday time. On the other hand, wind generation is higher on average during daylight time (Fig. 3), like solar. This might cause a net result similar to the duck curve (by increasing grid power uploading, rather than reducing demand), although periodicities and probabilities of highs/ lows differ from solar. It may be necessary to alter the timing of non-urgent freight and deliveries to respond to predicted grid needs (similarly to what already happens with industrial refrigeration), in line with weather forecasts.


Commuters’ EVs as energy deliverers
EVs will offer an additional opportunity. A future compact electric car with a 50kWh battery capacity can be envisioned as the “typical” vehicle (Tesla model S, a full-size car, has a 85kWh capacity with a 430km range). More than 15 million cars are driven in England and Wales every day for commuting, traveling an average distance of 16 km. Should all become electric, they would carry a capacity of 750GWh. In comparison, the output of the Three Gorges Dam in China, the world’s largest power plant, is 22.5GW: more than 33 hours of the Dam’s output would be needed to recharge these cars. On the other hand, such EVs could satisfy for 21 hours the entire England-Wales average power demand (about 35 GW), and the residential one (11.3GW) for almost 3 days. Commuting patterns often involve cars flowing daily from suburbs to business districts and back: this scheme moves battery capacity and energy from an area to another. 100,000 EVs, with fully-charged 50kWh batteries, driven 20km from home to work every morning, bring 46GWh in business districts, assuming a 4kWh consumption per trip. EVs with batteries significantly larger than needed for just the commuting round trip may be recharged either at home only, or at the workplace only: they can therefore carry energy from one place to another and still be able to commute. The average UK home uses 13kWh/day; a fleet of 1,000 EVs with 50kWh batteries, consuming no more than 10kWh on a return trip, could therefore supply a substantial energy share to the night time energy demand of a residential suburb. Electricity generated near EVs’ recharging locations will also reduce power grid’s load: this effect could be maximal for workplaces adjacent to wind/solar farms or other power plants.

Key messages

  • EVs are often foreseen as a means to stabilize the power grid by providing storage capacity. This vision requires that excess generation and demand peaks both occur when EVs are plugged in.
  • Adding EVs to the energy balance increases complexity and dependency on atmospheric conditions: with the “wrong” combination of climate and energy mix, the need for grid storage may actually grow.
  • Commuting, coupled to proper urban and socioeconomic configuration, may create a net flow of stored energy from residential areas to business districts and back. EVs can be harnessed not only passively, as storage means, but also actively, as energy carriers, to supplement the power grid in transporting energy.

Giuseppe Colantuono
School of Chemical and Process Engineering, University of Leeds

[1] Colantuono et al., Solar Energy 108, 2014
[2] Colantuono et al., Solar Energy 107, 2014
[3] G. Sinden, Energy Policy 35, 2007

Mobility & Energy Futures Series
Transport consumes a fifth of global energy and has a near-exclusive reliance on petroleum. As such it has an important role to play in the Energy Trilemma of reducing energy consumption and associated greenhouse gas emission, creating an energy system built on secure supplies and developing the system in ways which are affordable. Addressing the Energy Trilemma in the transport and mobility sector is especially challenging due to the continued growth in demand for the movement of goods and people, the technical, regulatory and social challenges of moving away from an oil based system of mobility and a complex and fragmented set of stakeholders required to work together to deliver change. Drawing on the expertise and opinions of the University of Leeds academics from different disciplines, this series will highlight the drivers, gaps and opportunities in reducing the energy consumption and carbon emissions from the transport sector in future. This is the fifth briefing in the series. Other issues in the series are available online at http://www.its.leeds.ac.uk/research/mobility-energy-futures-series

Bus services and social deprivation

New research by ITS and KPMG has quantified for the first time the relationship between bus services and social deprivation.

The Value of the Bus to Society report, commissioned by Greener Journeys, demonstrates the role that buses have in helping to reduce social deprivation in the UK, where 1 in 4 people is at risk of social exclusion, and 1 in 4 people do not have access to a car. It reveals that improving bus services boosts jobs and income for UK’s poorest people.

A 10% improvement in local bus services is linked to a 3.6% reduction in social deprivation across England, taking into account employment, income, life expectancy and skills.

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The research concludes that a 10% improvement in local bus services in the 10% most deprived neighbourhoods across England would result in:

  • 9,909 more jobs, the result of a 2.7% fall in employment deprivation;
  • 22,647 people with increased income, the result of a 2.8% drop in income deprivation;
  • 2,596 fewer years of life lost;
  • 7, 313 more people with adult skills;
  • 0.7% increase in post-16 education.

“If the Government is to meet its promise of making the UK a country that works for everyone, we must solve the problem of poverty in this country. As this report shows, buses play a central part in fighting poverty, keeping those on lower incomes or the unemployed, connected to economic opportunities. A good bus service can make the difference to whether someone can sustain a job, access vital public services or shop around for low cost goods and services.” Katie Schmuecker, Head of Policy, Joseph Rowntree Foundation.

The report presents the findings of a study that aimed to identify, articulate and quantify the economic, social and environmental impacts of frequent and reliable local bus services, considering the impact that bus services have on the ability of households to participate in economic and social activities and ultimately on levels of economic, social and environmental deprivation.

It builds on existing research by Greener Journeys which shows that buses bring huge economic benefits to the UK. Some 3.5 million people in the UK travel to work by bus, and these commuters generate more than £64 billion worth of goods and services per year. Furthermore, proper investment in local bus infrastructure delivers vast rewards, with every £1 spent on local bus priority measures delivering up to £7 in economic benefit.

About Greener Journeys
Greener Journeys is a campaign dedicated to encouraging people to make more sustainable travel choices. It is a coalition of the UK’s leading public transport organizations, user groups and supporters.  It aims to reduce CO2 emissions from transport by encouraging people to switch some of their car journeys to bus or coach instead. Switching from car to bus for just one journey a month would mean one billion fewer car journeys on our roads and would save 2 million tonnes of CO2 every year. Among its recommendations, Greener Journeys is calling on Government to prioritise investment in buses and local bus infrastructure. It is also asking decision makers to consider the wider social benefits of projects when appraising transport schemes and investment cases.