Crowd Dynamics: How to Prevent Crowd Crush Through Proper Planning- Image of Astroworld Travis Scott

Crowd Dynamics: How to Prevent Crowd Crush Through Proper Planning

Typically when you notice an old blog post of yours trending, it’s a good thing. In this particular case it’s actually just devastating. Back in 2015, our team at Decibel posted a blog titled “Crowd Dynamics: How to Prevent (and Survive) a Human Stampede or Crowd Crush.” At the time, we were reviewing the New Year’s Eve stampede in Shanghai, and the Germany Love Parade disaster of 2010 to learn how best to plan for and avoid these types of tragedies at events. With the recent event disaster at Travis Scott’s Astroworld concert, this post gained more traction as people searched to find out how something like this could happen. While the documentary and information on this post is still relevant, we thought it important to revise with current information, regulations and best practices.

As many of you know, Houston is my second home. While Decibel did not have a role in the planning or production of Astroworld, we do want to take the opportunity to present key learnings and provide best practices for our clients as they plan their events. What we will not do here is place blame, accusations, or conclusions for this particular event. There will be a time and place for that, but it is too early in the process to have any comment on this particular event before the investigations are complete. However, we firmly believe that no event should lead to an avoidable death or injury if it is planned correctly. So there will be many lessons learned here, and I am sure there were mis-steps along the way that could have telegraphed this in advance. This is avoidable, full stop.


Safety First Mindset
I will start by stating that at any large scale event, there needs to be a safety-first mindset. At Decibel, we are members of the Event Safety Alliance, and we recommend looking into the safety – mindset and track record of all vendors and promoters. For crowd management, there is a industry standard protocol for the planning of large scale events. This is covered in the American National Standards Institute document ANSI ES1.9-2020. You can download a sample here, and the entire document will run $40 from ANSI. We HIGHLY recommend reading and following this protocol on your events.


When producing large scale events, the plan is key. These scenarios must be anticipated, and a plan of action must be in place, in writing. This needs to be agreed by all principal teams onsite as to when this will be executed. In this scenario, the plan causes the action when certain criteria are met, and the human element is minimized in the heat of the moment.

One great example of this is our High Wind Action Plan that we at Decibel have in place for outdoor events. As the wind increases and hits certain speeds, there is a written plan as to what action is automatically triggered. Once we hit the max speed, a full evacuation is in place. There is no real-time conversation or discussion needed. It is pre-determined based on safety and stage tolerances and is set to execute. This saves time, limits discussions, and ultimately leads to lives saved. This scenario can also be in place for crowds as they get energetic, as crowd crushes begin and as the situation reached a danger level.

For crowd specific planning, this document focuses on the DIME-ICE matrix for analyzing risks and managing crowds. This stands for Design, Information, Management, Expectations, Ingress, Circulation, Egress. This is a great explanation of how to asses and plan for crowds. We highly recommend reading and following this matrix as you plan your events.


Sample DIME-ICE matrix during "Normal" conditions. For illustration purposes only. Your matrix must be based on the circumstances of your event.
Sample DIME-ICE matrix during “Normal” conditions. For illustration purposes only. Your matrix must be based on the circumstances of your event.



Venue Design
Safe venue design is paramount when developing your layout. Through this safety-first mindset, you can do your best to mitigate crowd crush and provide egress for participants. This is as important for outdoor events as it is for indoor events.

This is certainly one of the elements that will be reviewed in the Astroworld venue layout. One way of separating the crowd is through the  configuration or design of a “T-shape” dividing the crowd to stage left and stage right sections. A few other aspects to consider. It is important to avoid 90 degree interior angles, as turns should be rounded- this avoids compressive corners. Also, the more separate corrals or split viewing areas with ingress and egress will help divide the crowd, as well as allow medical and staff to arrive at emergencies as needed. I am sure CADS and layouts will be released in the investigation and I am curious as to how this was initially set up.

Stage Barrier Layout
Image of Stage Barrier T Shape Design


Aside from pre-planing and venue design, I really feel that communications are paramount when it comes to safety. At large scale events, cellular coverage can never be relied upon for any emergency. At Decibel, we bring in large amounts of radios for our events, and add repeaters as necessary.

Multiple Radios
Radios for Communication on Large Scale Event


Finally, teamwork is important. You can plan, design and communicate to your hearts content, but if all of the teams are not working the same plan, are not working together, all the rest can fall apart. This is one of our strongest attributes at Decibel- we put team above all else and it shows in our productions.


Other Considerations:

Covid and general attitudes are something we are really keeping our eye on as we emerge from this pandemic. After being in lockdown and distanced for two years, the energy of the crowd needs to be taken into account. This will be something to continue to reassess and review as we receive more data. But in addition to the interest of getting back in person, the energy of being around and excited, there is also a wave of aggressive behavior across the board. We are seeing this in the air and at restaurants, at businesses and at town hall and PTA meetings. Decorum has really taken a back seat with some individuals. I do not have a solution here, but it is important to keep an eye on in the coming months as we get back to events.





Articles on Astroworld:

Event Safety Alliance

Preview of ANSI ES1.9-2020

Decibel 2015 Blog:

Podcast regarding the incident outside a Who concert:
On December 3rd, 1979, eleven people were killed on the plaza outside a Who concert at Riverfront Coliseum in downtown Cincinnati. In this podcast, we will look at what happened that horrible night and what has happened since. We’ll hear from those who were there, those who lost loved ones, and from surviving members of The Who