Crowd modelling is the practical, operations based, planning approach to the development of robust crowd management plans. To develop a safe, robust crowd management plan you need to understand the following three step approach:
Crowd Modelling + Crowd Monitoring + Crowd Management = Safer Crowds.
Crowd Modelling : Site modelling, flow modelling, behaviour modelling, etc. The process of building a model follows the Discovery, Understanding, Control principles. We build models to discover the underlying dynamics of the situation or event, the process of building a model leads to a greater understanding of the situation or event and this leads to the development of a better control of the situation or event. Model building is the means to understand crowd safety in the complex and built environment. Please note there is a VAST difference between modelling and building a computer simulation. Models can range from line diagrams to coloured risk maps but rarely involve computer simulations.
Crowd Monitoring : Pressure suit, real time flow measurement, real-time density measures. Once we've modelled a site we need to implement measurement systems for real-time decision support. For the London New Year Event we have a series of stewards manually click-counting at regular intervals and perform a statistical analysis of the data, cumulating all entry points and forward projecting this data in the control room.
Crowd Management : Major Events Management and Crowd Management Plans. At all levels: Strategic, Tactical and Operational. Modelling is a process used in the development of a robust crowd management plan.
Crowd Modelling = Safer Crowds
Crowd modelling requires four key elements - Space, Time, Direction and Flow. The development of a crowd management plan may be essential to the overall safety if space/time/flow or directions of ingress/egress are restricted.
- what is the capacity at low/high density. Define each area in the site as a density profile. Different areas have different uses and therefore different crowd requirements (such as queueing, front of stage, bars, toilets etc.)Space
- over what period will the crowds arrive? Do you have sufficient welfare in place?Time
- which direction will the crowds approach the site? Specifically the loads from and to the local transport infrastructure.Direction
- what is the maximum flow rate of the arriving crowds - this determines the flow-fill-fail times. Some areas will require two way flow calculations and if space is at a premium then flow may need to be controlled.Flow
Complex sites may require some degree of simulation (for example where multiple, time related events occur in a complex street network, or planning a major event based around a transport infrastructure). For these types of problems, specifically if the site has never been used for major events, it can be useful to develop a simulation of the event. for that we would use more sophisticated tools.
Multi-discipline modelling approach to Safer Crowds
There are three different mathematical disciplines you can use for modelling crowded spaces in the complex and built environment. These overlap on most projects and a combination of all three are often necessary to analysis built and complex spaces.
Spatial Analysis - this involves assessing the capacity, lines of sight, utilisation, directions of approach, differenitating the types of spaces(for example walking, queueing, front of stage, entry and exit systems will all have different space demands)
Network Analysis - a technique used to assess the connections in the built and complex spaces, their relevant crowd flows and the relationship between flow and density in those spaces. How flows combine and how spaces fill are all defined in a network analysis tool.
Agent Based Analysis - this is the use of intelligent agents to simulation various crowd behaviours. It can be a very intensive and complex process and full of assumptions about how people may/may not react to changing environments.
Project Modelling and Simulations for Safer Crowd Management
Some projects require simulation depending on the clients needs and the complexity of the specific site. A typical client project outline is shown below.
