Addressing real-time challenge in real time evacuation calculations

05 Nov 2018

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By Arturo Cuesta, Daniel Alvear, Orlando Abreu, Adriana Balboa – University of Cantabria.
A timely prediction in the evacuation process of mass gathering events might well be crucial to save lives in case of an emergency.

Evacuation process is being performed by both hand calculations and computational models, mainly with a deterministic approach and high run times. These tools have been successfully used in different contexts and applications, such as engineering and planning. However, during an event management it is highly likely to be required a higher level of accuracy and results must be provided in real time. Therefore, there is a need to develop new evacuation models specifically for mass gathering events, stochastic and with the capability to perform several simulations within a few seconds for supporting decision making in real-time.

In order to rise above this problem, The RTE (Real-time Evacuation tool) is a software designed in the LETSCROWD project to calculate the evacuation of people in the crowd under different emergency conditions. Some of features of the model include:

Stochastic approach.
Microscopic and macroscopic simulation.
Results in cuasi real-time (within a few seconds).

How the RTE works?

The model handles both indoor and outdoor scenarios. Geometry is configured by simply assigning the number of available exits and their width. The evacuation is calculated as the sum of two components: 1) time for the first pedestrians to reach the available exits and 2) time for the rest of population to flow through the available exits. The first component is calculated by using a microscopic approach whereas the second component is obtained by a macroscopic approach. Response times, travel speeds and flows through the available exits are stochastic variables in the model. Monte Carlo methods are used to generate samples of the input variables and the model has the capability to perform hundreds of runs to capture stochastic variations in the outcomes.

The real-time applications require processing the outputs quickly enough and the information provided need to be easy to interpret and with a high confidence level.

The model provides the significant evacuation time for each exit defined as time from a collection of (total) evacuation times that is greater than or equal to a threshold value to be defined (i.e. 95th percentile). It also provides the optimal proportion of the population per each exit available.

The RTE tool allows the user the possibility to make exits unavailable due to the emergency and explore the potential results.

The information provided by the model will help the security decision makers to:

Predict the required safe escape time for people involved in the emergency
Implement faster and/or safer evacuation procedures
Assess the impact of current/potential emergency situations
Plan intervention strategies

To sum up, RTE tool is an outcome of LETSCROWD that aims to solve a major problem during emergency management actions in a terrorist attack, since enhancing evacuation operations might be crucial to guarantee the protection of people involve in these situations.

LETSCROWD components and aspects