Planning for passengers
The argument for pedestrian simulation in transport planning and management would seem to have been won
The best way to prevent station congestion and safety concerns is through simulation, it is just a matter of deciding how you want to use it and what features you need says Erin Morrow, product director at MassMotion.
Preparing for the future
Catering for growing urban populations is the common theme underlying transport infrastructure projects across the globe, be they multi-modal hubs or outlying stations being upgraded with automatic ticketing and gates.
Railways exist to get people from A to B in a way that is comfortable and safe for them, and which enables operators to maximise the use of lines and keep to increasingly tight schedules. There is rarely room for the slightest error: a single escalator breakdown, or even someone in a flowing crowd stopping, can cause expensive knock-on chaos.
We are all equipped with predictions on populations and passengers, but what is the best way to use these numbers? Statistics are helpful, but applying them intelligently can help to inform network design and ongoing operational management. This in turn can minimise the risks of major disruptions being caused by relatively minor issues. Pedestrian simulation has proved itself to be the answer to these important questions.
You will have seen visualisations of how crowds will flow through a building, but might not have realised that what you see is much more than an artists’ impression or a visualisation of what engineers assume will happen. It is, in fact, probably as near to real life as you can get.
The actions of the virtual people within the simulations are driven by accumulated research into human behaviour over decades, coupled with field observations. You can start the process by either importing 2D or 3D models into the software or by building your 3D model from a blank canvas within the software itself. Then, identify the exit points and the number of virtual pedestrians you would like to simulate.
This allows the software’s algorithms to define the crowd profile, giving individual characteristic speeds, ages, and preferences to create a realistic mix. Thereafter they make their own value decisions about their journey: in other words the software should be non-deterministic.
If faced with a blocked escalator and an empty stair, these agents will take the stair (so long as they are not programmed to represent the proportion of the crowd that will be, for instance, elderly or incapable of doing so). The software will also take into account local habits such as giving way to the right or left.
In a virtual world you can block a stairway, add a few hundred more people on a platform to simulate a train cancellation, experiment with fewer or more ticket barriers etc. and see what would happen in the real world.
Benefits of simulation
It costs virtually nothing to correct design errors on screen; and a lot more to run trials in the real world. Your commercial teams can work out the best locations for high-rent retail concessions.
You can also, of course, run emergency evacuations and test your egress planning. Holding the technical lead here is Oasys MassMotion, which also has the capability to import transport timetables, allowing your simulation to be as accurate as possible.
MassMotion has an illustrious list of projects it has been used on, including Toronto’s Union Station, New York’s Fulton Center, a major transport operator in South East Asia and various international airports.
Pedestrian simulations run on models that are easily built by importing existing assets, including CAD files and BIM objects, that are part and parcel of any development programme and readily available.
So, as MassMotion product director Erin Morrow says; ‘The argument for pedestrian simulation in transport planning and management would seem to have been won. It is just a matter of deciding how you want to use it and what features you need. In 2017, I would put genuine 3D analysis, more intelligent virtual passengers, speed and scalability at the top of the shopping list.’
Not surprisingly, all of these feature in his team’s software.
Models and analysis
3D is vital, and it should mean 3D analysis, not just 3D visualisation of 2D overlays, Morrow goes on to say.
Earlier simulators had people disappear in front of a stairway and then reappearing at the top. Anyone who has ever walked through a station will know that makes no sense. If you want to optimise the whole passenger journey, you have to see and resolve all the bottlenecks and dangers that emerge within a real-life multilevel building, and stairs and escalators are a major concern.
The intelligence of these virtual passengers continues to increase. In the latest release of MassMotion, users also have tools to tailor the built-in algorithms and define venue specific external trigger events such as acceptable crowd density, running out of seating space or even exceptional weather or events.
Agents in a MassMotion model will then respond intelligently to these external triggers as well as the internal agendas they have been given.
Speedy analysis is another key benefit of modern simulation. Where desk-bound CAD engineers used to take days to build a simulation model, it is now quickly built by importing other assets. User interfaces make programming scenarios easy and results can be generated in minutes or at most hours for very big multiday simulations, not the days it used to take.
Simulation and analysis has become inexpensive in terms of time and effort to query the model, to experiment with different scenarios, to develop informed plans for managing people during planned or emergency maintenance or for major sports and cultural events. Smarter virtual agents that will react to external triggers as well as in-built algorithms have now been introduced by the MassMotion developers, adding more granularity to your analysis.
Scalability is how you future-proof your designs. Will they cope with the passenger predictions you have? Even if you have no need of extra escalators or gates now, when will you? And where should you allow space in your original design for them to be added?
Simulation software has its origins in emergency evacuation.
A few years ago Oasys helped to run a MassMotion comparison between a modern sports stadium and the Colosseum of Rome. In the simulation, the Roman building won by a hair’s breadth – it evacuated in a few seconds less than the modern structure.
However, the scale of the simulation was quite small – an average Colosseum crowd was around 65,000, compared to 100,000+ these days – and the scenario was simple: just leave your seat and exit the building.
Designers of modern transport hubs have much more complex scenarios to manage. For instance, Singapore’s SMRT carries well over two million passengers a day in fluid configurations. New York’s Fulton Center, designed with the assistance of MassMotion, caters for 300,000 passengers daily.
This means that while the basic building design principles for pedestrian flow have been understood since Roman times, you cannot just transpose them to modern construction. The core challenge today is handling a growing population and pedestrian simulation gives you a window on how to manage that growth.
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