IEEE Technology and Society Magazine - December 2019 - 64

By modeling users as individuals,
specific human behaviors can be
accommodated.
behaviors, or they may miss some of the variance in
these behaviors.
Modern computational and research capabilities
allow us to investigate the impact of different designs to
a far higher resolution. Pedestrian dynamics is a key
example of this design paradigm. Pedestrian dynamics
is a process whereby the designer attempts to produce
a model of human behavior within the infrastructure
project, aiming to replicate the real behavior of the individual users. By modeling users as individuals, it is possible to investigate the extremes of the design profile,
and therefore to accommodate the specific human
behaviors that had been previously grouped together
with the rules-of-thumb approach.
This article aims to discuss both the potential benefits as well as the ethical concerns of using a pedestrian
dynamics approach in the design and retrofitting stages
of large-scale infrastructure projects. It will be seen that
this approach can have huge impacts, both in the dayto-day life of pedestrians, but also in the ultimate outcome in emergency situations, as human behavior
becomes more unpredictable. Furthermore, this
approach can serve to significantly improve access and
mobility in cities by highlighting problems automatically.
This article will go on to argue that these potential
benefits can only be realized if there are significant
efforts to include all demographic groups. This will
require a large amount of "basic science," dataset gathering that will allow researchers and industry professionals to incorporate specific measurements into their
models, rather than using average values. This will also
require a concerted effort to verify and validate existing models, and provide a methodology to do this with
future models. Without addressing the challenges considered in this article, the benefits offered by pedestrian
dynamics will largely go unrealized.

Pedestrian Dynamics
"Pedestrian dynamics" is catch-all term that refers to
both an industrial engineering tool as well as an active
area of research. The term's origins go back to the
1950s [2], maturing in the 1970s [3], [4]. It has seen a
large increase in popularity with improved access to
computational power since the early 1990s, and the last
thirty years have seen a huge expansion in the

availability and commercial viability of pedestrian
dynamics software models [5]. Numerous types of representational models have been created, ranging from
highly detailed agent-based modeling [6] to more
abstracted fluid-based approaches [7], depending on
the design requirements and the scale of design being
examined. Currently there is no one model that can do
everything, but rather lots of different models that can
investigate specific situations. Each of these has their
own benefits and drawbacks, depending on the design
aim; some can capture how individual pedestrians will
move around obstacles, others might be able to predict
congestion zones in real time, or focus on the decisionmaking process that leads to an individual selecting a
route in the first place.
These have typically incorporated very simplistic
models of human beings, having singular destinations,
no ability to change goals and no way of modeling
social ties to other simulated agents. It is relatively easy
to implement these "ball-bearing" models, but as this
doesn't reflect the reality of the situation, in many circumstances it is narrowly applicable. Instead, recent
efforts have focused on defining and incorporating psychological elements (social or familial groups, emotional responses, etc.) into models [8], so that engineers can
fully investigate realistic scenarios.

Current Usage
Pedestrian dynamics models are regularly used in modern construction projects, and by event and crowd management companies. The London Olympics and
Paralympics (2012) used this modeling significantly to
improve the design of the Olympic village [9], ensuring
the routes from the various stadia were not too congested, and alerting the crowd management team when they
needed to deploy staff to control congestion. Similarly,
the London Crossrail project uses pedestrian dynamics
[10] approaches to investigate the routing of passengers
to ensure that the width of platforms and the numbers
of exits (among other design features) are scaled appropriately to accommodate the predicted usage.
In addition to designing new projects, pedestrian
dynamics also impacts on the management of existing
infrastructure. For example, if the owners of an arena,
originally designed for dog shows, want to understand
the impact of hosting a Real Ale festival instead, then an
engineer would create a model that incorporates the
behavior of typical Real Ale festival attendees, as
opposed to those of dog show attendees. This might be
an interesting research task, finding differences in the
number of attendees, the demographic characteristics
of these attendees, and the typical behavior observed.
A specific example is where an engineer would investigate the expected inflow/outflow at the entrances to the

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DECEMBER 2019

IEEE Technology and Society Magazine - December 2019

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