The thought process and decision making in effective Queue Management Systems
Efficiency and design Part 1
As this is a blog and not an academic piece of writing, we are not looking to provide scientific facts and figures; although we may use a bit of basic number crunching to illustrate a point or two. We would advise you to explore this topic more in depth as it plays a massive role in crowd management.
May we recommend you start here –
Why do we queue?
Well the easy answer is, if we did not, life would be a lot more complicated and less orderly. Is it though politeness, the need for order and conformity for things to run smoothly or over the years we have accepted that if someone arrives before us, they should enter before us? The psychology of people and crowds and why we behave in certain ways is fascinating and we could only scratch the surface and would not do it justice. So for the benefit of this blog we are going to follow these sets of rules – customers will follow signage and instruction in a management system that is systematic and easily understood.
Why do queues form?
Life would be wonderful if we never had to wait on anything, every door was open, we all gained access without a break in step; but sadly that is not the case. There are a few reasons a queue can form at an event
- We arrive before the place we want to enter has opened, so have to wait.
- There are more people looking to enter that can pass through the opening
- A delay in entering created by ticket checks and security checks
So what do you do?
The arrival at an event is your customer’s first point of contact with you on the day of an event. How they got there you can influence and advice on, but there are influences that are out with your control. Hopefully the weather is nice, there form of transportation was efficient and they are looking forward to an enjoyable day. It is within your defined area of external communication that you can start assisting in controlling your customers and assisting them in having a pleasant arrival.
To assist with going through the blog we will look at a site to work on and try out queuing systems. We have chosen to use and urban Green field site to work with. There are a few reasons for this; transport plans are in place thanks to public transport, there are confines to work within and most people can understand what is in a park rather than a field in the middle of nowhere. For this, we have chosen Hyde Park in London; a well known park in one of the busiest cities in the world. But more importantly, it is well mapped on Google Earth and has captured an event space already in place.
The space indicated within the Yellow lines is the area we have to queue all our customers, for the sake of discussion – 50,000. The area within this is 25,537.97 meter square; give or take a few. We can start putting people into this space along the lines of the guidance provided by the Event Safety Guide (Purple guide).
1ppm2 = 25,537 persons
2ppm2 = 51,074 persons ( so we know we can accommodate the capacity of the event )
3ppm2 = 76,611 persons
4ppm2 = 102,148 persons
If we follow the guidance for an event then, we should recommend that the crowd density in a queuing system should be 2ppm2 and at no point higher than 4ppm2. Higher than this we know that crowded spaces can be dangerous. We also have to factor in that the higher the density then the more difficult and slower the flow of people will be when they start moving.
What else do we have to take into consideration?
There are always factors that we have to take into account when we want to take control of a space to create a queue management system.
- Condition of the ground. Is it in good condition, are there pot holes, is there long grass, maintained grass, sand, tarmac or paving,
- Where do customers enter the queuing system. How do they arrive at your event space- train stations, bus stops, car parks….
- What are the weather conditions? If it is inclement, will you customers queue in the rain or snow? Will the ground conditions create pools of standing water that will encroach on the space used for the queuing system? (People don’t like standing in pools of water and will avoid them)
- Is there street furniture or fixtures that are in place before you arrive and have to take into account.
- Does the area you are using have public rights of way?
- How many people do you expect to be queuing? Are you customers going to turn up early?
- How early will your customers arrive, and do you need to provide facilities for them.
- Are your customers going to be compliant to using a queuing system or prove challenging.
As this is a blog to look at efficiency and design we should set our guidelines – the ground is in good conditions and drains away water well, all customers come from the North, there is no street furniture and the audience is compliant. The public paths are rights of way though, so we cannot queue customers on them.
We should really look at how people queue, if we are to understand how to manage queues. It is something we do in everyday life, normally in shops, banks and for transportation. From a very young age we are bought up in a way that allows us to understand that when waiting to either enter somewhere or be served, we stand behind the person in front of us. If we are by ourselves we will fall in behind the one in front; so if everyone is by themselves we end up with a large single file. If we are with someone else, we would normally stand next to one another. This allows for a more convenient conversation to take place, as this is how we present ourselves when walking forward. If we are arriving in larger groups, we start to fall in behind one another. This keeps the group together and allows us to turn around to talk into the group rather than the more difficult option of passing the chat up the line. In this manner, we as queuing customers dictate the width of the line if there is no management in place.
What can cause problems is when we attempt to queue in large numbers or in areas we are unfamiliar with. Our whole lives we are guided through or days with information, signage, paths and roads. We are taught to read the signs to give us the information on what way to go. By following on the paths provided we can reach our destinations. As we progress through life a high percentage of us start driving. This is when information is vital to us in our quest to reach a destination. We are trained that by following all the information provided we will get from point A to point B. But, what happens when we turn up at a field that someone is putting a concert on and there are no signs, we do not understand, there seems to be people everywhere and what looks like a queue, but it seems to go where it wants, but where is the start of the queue and where is the end and our final goal.
After we have accepted that compliant people can queue when required, we next have to design a queue management system that the customer will use. Lets look at three of the most popular.
A single queue
This generally forms a long line with customers systematically behind one another. This can be seen at supermarket checkouts, cash machines and such.
What do you do when you can end up with a lot of customers and not a lot of space to use or you just do not want that long line snaking everywhere. This system gained popularity via Disney at their theme parks; to prevent the snaking queues everywhere and compressing them into a smaller space. This has been adopted everywhere from airports and banks all the way through to zoo’s.
When dealing with high volumes of customers there is also the option of creating holding pens. This allows you to gather large numbers in one area before moving them.
It should be noted that although you are defining an area for the customers to occupy, either out of barriers, rope and post or tape, you must comply with the guidance provided and control the area. You have in a basic form created a designated event space and as such must control the capacity. Creating high density can create a crowd related incident in the worse case down to being an unpleasant customer experience.
So where do we begin?
We know the following facts – 50,000 customers, good ground for queuing, customers will come from the North and they will be compliant to a management system. What else would be helpful, a bit more on the customers would be good.
Will the customers arrive early or late? Why would this be useful?
Early arrivals mean that they are going to be queuing for a while; this could be hours before we open the venue. We want to make sure they are well rested and relaxed, they have decided to have a very long day and if they are tired it can lead to problems front of stage later. To allow the customers to relax we have to provide them space, to stand, to sit down or move.
Late arrivals also need space to queue, especially if they all decide to arrive at once. Unlike early arrivals though, these customers want to keep moving; they know the longer they wait the more likely they will miss part of the show. Due to this they will want to keep moving, even slowly; as long as they keep moving. With this they will accept higher density, as they get closer to the people around them to give them the feeling of moving forward. If we put these customers through a Disney style system it will cause frustration as they will be travelling a greater distance and getting no closer to their final goal.
Understanding a bit about our customers
We are all individuals, have our own thoughts and ambitions. We set our own goals and achievements. Thankfully for those that have to plan for events, we can profile our customers and put them into a box and label them (sounds terrible does it not). We all follow certain social norms and as such can be grouped under headings. If we look at a football fan that follows a certain team; they sing certain songs, follow news on the team, the team’s performance can influence their fans mentality (happy, sad, aggressive, defensive, arrogant). In understanding our customers and how they can react and behave, we can cater the management systems we build to suit our customers.
How will our customers arrive at the venue?
Sounds like it should have nothing to do with us, who cares! Well, how a customer arrives at a venue tells us a lot about them. Let’s look at certain parts of how our customers get to our venues.
- By car. The first thing, we have a high percentage chance of saying is the driver will not be drinking; well we hope. It also means they are going to try and get close to the venue. This takes planning on the part of the driver, forward thought about what they are doing. They will need parking, they are going to want close so they don’t have to pay for public transport. If the parking in the local area is expensive they may be looking for free parking. If the driver is not affluent the cost of parking can be upsetting so will be looking for the days entertainment to justify this. By looking for parking areas we can gauge where a percentage of the audience is coming from.
- By bus, train, subway. Our customers have a specific debarkation point from where they arrive. They will be looking for the closest ones to the venue, why – would you want a 20 minute walk after being on some mode of transport. We can look for where these debarkation points are, what the timetable is, the average capacity of the vehicle. This allows us to determine how many people will be arriving at our management system within a given timeline. If you pair this with the profile of early arrivals or late arrivals you can fit you management system to account for this.
- Local community. Are there a percentage of your customers coming from the surrounding area? This all depends on the type of event you are offering. Is it aimed at the local community, is it free or admission fee apply, the entertainment on offer is attractive to the local population. The customers from the local community will probably walk to the event. They will have an influence on the event through imprinting the area that surrounds the event on to the event. Again by understanding where and how many of the local population are attending, we can create an arrival profile.
Through looking at the customers we are expecting to attend we can create a queue management system and solution that is suitable to the requirements of the event and the customers. These systems should be reviewed for each event though. Every event is different; is this not part of the attraction. We need to think about the time of day, weather, threat level, age range, sexuality, sex ratio and a hundred other different influences.
Looking at what system suits best.
To do this we can look at the site we have chosen and virtually test out systems to see if they are suitable. Why would we do this? It is a lot easier to try ideas out on a bit of paper and computer that physically moving barriers and laying out lines.
A very simple barrier system; a straight line leading to the entrance. What calculations can we make from this planning stage.
Length of queue is 40meters.
Length of entrance is 66meters.
This would allow us to create 66 entrance lanes at a 1 meter width. If we follow guidance we know we can put 2 customers in each square meter.
2 customers per square meter
X 40 (length of queue)
= 80 customers per lane
X 66 entrance lanes
= 5280 customers can occupy the queuing space.
The next part we need to know; is how fast the customers can process through this area, as we have 50,000 to pass through the area.
The rate at which a customer will pass through the entrance will vary in line with all the other factors that we have to think about, but we can calculate a possible solution. The Guide to Safety at Sports Grounds provides us with the rate of entry at a stadium turnstile – 11 persons per minute. We can use this guide to assist in calculate our entry rate (consideration must be made as to being able to match this rate of entry at your planned for event. If you do not match this speed, your queues will grow).
X 11 persons per minute
= 660 persons per minute can pass through the entrance
How long does it take to clear our queuing system –
5280 in the lanes
/660 persons per minute
= 8 minutes to clear the queue
= 76 minutes to clear 50,000 customers
With this information we now know that we can clear the queuing system within 8 minutes. We also know that as long as more than 5280 additional customers arrive within these 8 minutes, then the queues will not leave the lanes.
To create 66 lanes 40 meters long, we are going to require a substantial amount of barrier. We can also see a deterioration of the lanes; customers dropping rubbish so creating trip hazards or barriers being moved out of line. These can decrease the efficiency of the lanes; they may have to be closed to be cleaned. There is also gaining entry in the case of a medical emergency and the close confines of the lanes may make it difficult to reach and retrieve patients.
We can look at a different system to implement and see the results from this system. For comparison we will use the same amount of space as the first test.
We already know that the space holds 5280 persons according to guidance. So where is the difference? That would be in the distance that the customer has to cover to reach their final goal.
Test 1 – 40 meters travelled by the customer
Test 2 – How far does the customer travel to move forward 40 meters (depth) towards the entrance.
66 meters (width of the entrances)
If we make the width of the same as the first test of 1 meter, then we would have 40 lanes to create to cover the 40 meters (Depth) towards the entrance
66 meters (width)
X40 meters (depth)
=2640 meters the customer would travel.
I think we can agree that we are going to have a very tired and annoyed customer; turning back and forth walking all that distance and not seeming to get any closer to their goal. How do we reduce the distance the customer has to travel? We could make the lanes wider, so reducing the amount of turns.
How wide do you make the lanes though?
2 meters = 20 turns = 1320 meters travelled.
4 meters = 10 turns = 660 meters travelled
5 meters = 8 turns = 528 meters travelled
10 meters = 4 turns = 264 meters travelled
By widening the lanes we can reduce the travelling distance covered. We have to think about the customers though; the idea is that we are attempting to create a controlled system.
2 meters = 4 customers wide
4 meters = 8 customers wide
5 meters = 10 customers wide
10 meters = 20 customers wide
When we start getting towards the top end of these figures can we really control the customers the way we want to. There is then the question for efficiency of the system. The human factor impacts on the queue.
It will not take long for customers to think about how to get through this process quicker after they have entered it (think rodent in a maze). We will quickly figure out where the turn is and aim for this. This will mean that we will lessen the space between one another to allow us to get around the corner by a shorter path.
This creates a few problems for us, first is at the corners. As people get closer to one another we no longer have an even spread of customers and gaps appear in the corners at the turns.
With an uneven density of customers passing through the system, we will see a breakdown in the efficiency of the passage of customers. With an increase in density at the corners, we will see a decrease in the speed at with customers move. Normally this would be unfortunate but not an inconvenience. To realise why this is an inconvenience, we can go back to the people using the system. Are they in groups, couples or single. If you have a group of people moving through the system, it is unlikely they are going to move through in a line abreast so ensuring an orderly line behind them. If it is two groups of couples, they may stand next to one another as they arrived close at the same time. The need to pass through the system faster than others will be present in some of our customers. We are not saying they would push past the person in front, but they would look for ways of passing past those in front without it causing physical contact. It is in the corners again we will see this happen. As the density at the bend increases and gaps are left in the corners, we see open space that they would be winners will try and move in front of the person in front of them. By moving into the space available the pace of the customer will be swifter than the slower moving customers that are more tightly packed in the turn.
This inefficiency of this queuing system can cause frustration and upset among our waiting customers. The will expect to enter the venue in the order that they arrived and the thought of someone that arrived after them will cause displeasure. The differing in density as customers moving through the system can also be unpleasant. Our customers may not want other people encroaching on their personal space.
Although we are pointing out some flaws in this queuing system, it is still as popular as the day it was created. When you increase the width of the lanes though, you lose some of the efficiency of the process. There is also the risk of customers ignoring the path that you wish them to follow. If the lanes are not full through the system, you risk the customers making their own short cuts; climbing over the barriers, opening the barriers or pushing them over. We would have to monitor the lanes to ensure that we are not making customers walk unnecessary distances. This requires making short cuts for the customers in a controlled manner.
Pen queuing system
We guess the best way of describing a Pen queuing system is to look at livestock. Yes, we know this is a very unfortunate picture to paint, but is very popular when handling large numbers of livestock. A very simple construction, that is created to hold a large number of customers; entering at one end and leaving through the other. This system requires a period of time where customers are held until ready to be moved on to the next stage.
Once again we have looked at the same area as our previous two systems. With that we can expect the same number of people to be held in the area; 5640 persons. This is spread across the pens created. As each pen is a designated size, each will have a capacity. If we are looking for efficiency, we would ensure that each pen is filled to it capacity. A simple system to operate
Fill pen 1 from one end and the customers will leave from the other end
When pen 1 reaches it capacity, start filling pen 2, repeating this process to pen 3.
On opening, pen 1 is emptied first, moving onto 2 and 3 in turn on completion of emptying the pen before it.
When pen 1 is empty, we can start filling is as long as the rest of the pens are full.
If at any stage during the process we find that the pens are empty of waiting customers and we have a steady walk up that is not causing queues then the system is complete and a free flow operation will be implemented. The area will be monitored in the case of a build up of customers and the pen system can be restarted.
Although this can be a simple system to operate, it does require management and compliance. The operators of the pen have to ensure that it flows and it follows the correct order. There has to be willingness for the customers to use it. As the customers are filling a larger area, they must be willing to accept to a certain level that those that arrive after them may enter before them.
As with every area that has a capacity, it relies on the customers spreading evenly across the space. If the customers group in closer together than planned for then it can look like there is a lot of empty space in the pen, even though the capacity tells us that it is full. Continued filling of the pen can lead to high density and risk.
Although we have only looked at three of the most popular forms of queuing, it has allowed us to consider the pros and cons of these queue management systems. Through looking at our event spaces, our customers, surroundings and travel arrangements we can plan a suitable and efficient queue management system.
Workingwithcrowds.com 18th November 2015