Space and the city
Immersive virtual models are helping enhance the development of transport spaces, improving user accessibility and saving money and time on projects. Brendon Hooper reports
City populations around the world are growing, with space becoming increasingly scarce. According to a forecast by UN-Habitat, 70% of the global population will be urban dwellers by 2050, which will put further pressure on public infrastructure.
As many city commuters already know, large numbers of people flowing down a narrow set of stairs, or through inadequately spaced walkways, can quickly lead to congestion.
To tackle these challenges, planners and engineers behind some of the biggest transport projects are turning to the technology of virtual simulations.
High quality 3D technology seems to be everywhere in our culture – in films, television, video games and in-car navigation systems. As design software has progressed, the virtual world has also become integral to the planning stages of developments.
This is because virtual models are able to visualise how vast numbers of people move around and use the built environment, so problems with the original design can be identified early and eliminated from final designs before foundations are laid.
Attempts to model the movement of people in complex spaces can be traced back to the 1920s, when urban planner and former RIBA president Sir Raymond Unwin studied the relationship between buildings and pedestrian flow.
In one study in Chicago he found that, at peak times, five-storey buildings could discharge nearly 2,000 people in about six minutes. His findings were used to inform how exits should be designed and how congestion outside the buildings could be mitigated.
Further investigation into the movement of people is rooted in J.J. Fruin’s influential pedestrian planning and design research from the early-1970s. Fruin’s groundbreaking research found that pedestrian flow speeds are roughly normal up to an average pedestrian density of 2.32 sq m per person.
After this point, walking speed declines rapidly with congestion and reaches zero around pedestrian density of 0.28 sq m per person. To define the degrees by which traffic is flowing, Fruin devised the Level of Service (LOS) system, using the letters A to F – with A being the best flow and F being the worst flow.
This technique is still used by US highway engineers to define motor traffic congestion today.
Recurring congestion
More urban dwellers mean more passenger journeys on public transport and an increase in the potential for recurring congestion.
Figures from the UK’s Office of National Statistics show railway passenger journeys in Britain have nearly doubled from around 700m per year in 1986 to 1.3bn per year in 2009.
In Zurich, a major European city and international transfer hub, passenger traffic is expected to double by 2030 from its current level. Swiss Rail plans to introduce double-decker trains to cope.
Expanding the size of trains to handle larger numbers of people is one good idea to alleviate passenger congestion, but how do we ease the congestion on platforms, stairs, at ticket gates and exits?
By testing flow models of people’s movements in virtual replicas of developments, the potential for problems in the final development can be reduced, saving money and time for developers, clients and passengers alike.
“The cutting edge of urban modelling now represents populations as individual agents whose movement within the city is the focus,” says Michael Batty, Bartlett Professor of Planning at the Centre for Advanced Spatial Analysis (CASA) at University College London (UCL).
Batty and his colleague at CASA, Andrew Hudson-Smith, have created and tested virtual models of people using dense entertainment areas, such as Covent Garden in London, which attempt to understand how visitors negotiate space on a first-person perspective.
“Our aim is to replicate real behaviours and then embed these within the virtual scene, visualising agents in 3D and getting them to move through the virtual city.”
This testing of virtual possibilities is helping in the planned £695m refurbishment of London’s Victoria Station, a major transport hub and home to the busiest Underground stop, with more than 76m passenger journeys a year.
During peak periods, the Underground is frequently unable to cope and often has to close temporarily because of overcrowding.
These closures can sometimes occur up to five times a day as thousands of commuter passengers converge at narrow access points off the platforms and at the entrance to the Underground.
Upgrade work
In order to enhance the user’s experience of Victoria, it is imperative that any upgrade work should take into account how flows of people access certain areas of the station.
“3D modelling helps us understand how a design of a building may have to change in order to meet the needs of the people using it,” says Chris Stutz of Space Syntax.
The company helps built environment professionals understand the importance of spatial layout and spatial accessibility, and that the structure of a space influences the behaviour of people.
Space Syntax has developed software tools that evaluate the role of spatial layout in shaping patterns of human behaviour.
These tools have helped inform research in the upgrade of Victoria Station – the contract of which was recently awarded to Taylor Woodford/Bam Nuttall – as part of a UCL project called RACMIT (Refurbishment and Customer Movement Integration Tool), and in partnership with Network Rail, British Land, Laing O’Rourke and Buro Happold.
“Our research started with a real-life observation of the day-to-day life of the station and how people navigate through it,” says Stutz. “This would include where people come off trains, move across platforms and concourses, use entrances and exits, and where people congregate around shops and waiting areas near the information display boards.”
After two or three days of continuous monitoring, the team built up a set of data that showed an accurate picture of the emergent behaviour of passengers.
The modelling software (pictured above) helped recognise potential ‘pinch points’ where large flows of people are squeezed into narrow spaces.
Furthermore, these models not only help alleviate potential future problems by identifying them at the planning stage, but can also help spread customers around particular zones of the station, such as retail sections, making sure all space is utilised effectively.
“We can work with local authority planners, developers and property consultants, and say ‘this is the role space will play in your design’. We can also think about what to do with empty ‘dead spaces’ that people don’t use – such as those unused areas in a shopping mall – and consult on how to optimise the flow of users to this space and create business opportunities.”
According to Transport for London (TfL), the overall improvements to Victoria aim to cut peak time congestion and improve capacity.
When completed, the scheme will increase the size of the station by about 50%, with a new ticket hall, seven new lifts and additional escalators to ease congestion, as well as step-free access from street level to all platforms.
Mirror worlds
“Virtual urban environments allow the stakeholder a holistic look at the complexities of a city, so they can ‘walk through’ the area and experience any potential challenges to the design,” says Terrence Fernando, director of Think Lab at the University of Salford’s School of the Built Environment, where virtual urban worlds are created as total space concepts to be tested.
“We are able to make conceptual mirror worlds, which integrate different sets of land data and can help such things as public consultations to look at the initial impact a design might have on people’s lives.”
One example where a Think Lab simulation helped stakeholders visualise the scale and accessibility of a project was on the consultation of a new tram network in the Midlands.
It helped join up the thinking for parties involved, not just visualising where the tram network would interact with the road network and pedestrians, but also how it would impact on non-visual factors, such as land values.
So it is not just the structure of the built environment where 3D technology is being applied – it is being innovatively used in visualising non-physical aspects, such as land ownership, rights and values.
Last year, Professor Roland Billen, of the Geomatics Unit of the University of Liège, produced an RICS research paper exploring the needs of a 3D urban land register.
“Geomatics surveyors,” he explains in the report, “used to working with photogrammetry and land surveying, are quite familiar with 3D approaches, and have started to develop 3D urban models, in collaboration with computer scientists, urban planners and architects […] These models can include juridical objects (individuals, institutions, companies), fictional objects (administrative boundaries) and abstract objects (taxes, deeds, incomes) […] By using 3D city models, it is possible to visualise what a city will look like after a proposed change.”
Virtual environments are helping clients and local authorities see the bigger picture when considering the flow of people and traffic within an urban environment, enabling planners to improve route efficiency and accessibility, and at the same time ensuring that moving elements, such as vehicles and pedestrians, interact safely.
“I think there is massive scope for virtual modelling to be used at a design stage,” says Andrew Hudson-Smith. “We’re now seeing the virtual world applied in real time – for example, using crowd sourcing applications, relayed through people’s smart phones, that gather up-to-the-minute data on traffic flows and feed them into the model.”
Above all, it is a lot cheaper to correct bad design ideas in the virtual world before they are built in the real world.
Roundabout solution
Over the next decade a £1.5bn, 300,000 sq m regeneration programme of Elephant and Castle in south London will see the creation of a new pedestrianised centre, market square, green spaces and thousands of new homes.
Southwark Council approached Space Syntax to design proposed virtual environments for a new central roundabout that would balance the needs of pedestrians and vehicles.
“We found that with the existing layout, pedestrians were generally sidelined and would rarely use the subway under the roundabout, preferring to sometimes jump over the pavement barriers,” says Christian Schwander, a town planner and architect at the company.
Transport for London also insisted that the new design should not create more delays for vehicles, while at the same time make it more accessible for pedestrians.
“We modelled a number of different options for a pedestrian crossing, but eventually settled on a triangular shape. This enabled an easy-to-navigate system with three way-finding points.
By using software to simulate how the junctions would be used, the developer can see where it will be easier for pedestrians to cross a busy junction, increasing their safety, yet not hampering vehicular access to the junction.”
Further information
www.rics.org/geomatics
www.rics.org/research
www.thinklab.salford.ac.uk
www.casa.ucl.ac.uk
www.spacesyntax.com
