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Walking the Tightrope: Designing Autonomous Vehicles for Comfort and for Sustainability

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Abstract

Given current traffic problems, transport-induced air pollution and climate damaging emissions, researchers are investigating potentials of autonomous vehicles (AVs) to contribute to a more sustainable mobility. Some studies, however, indicate that the introduction of AVs may cause rebound effects that could further harm the environment such unintended modal shifts. Currently focusing on user experience design, there is an urgent need for HCI researchers to consider such negative consequences in order to responsibly design sustainable AVs.
Walking the Tightrope: Designing
Autonomous Vehicles for Comfort and
for Sustainability
Abstract
Given current traffic problems, transport-induced air
pollution and climate damaging emissions, researchers
are investigating potentials of autonomous vehicles
(AVs) to contribute to a more sustainable mobility.
Some studies, however, indicate that the introduction
of AVs may cause rebound effects that could further
harm the environment such unintended modal shifts.
Currently focusing on user experience design, there is
an urgent need for HCI researchers to consider such
negative consequences in order to responsibly design
sustainable AVs.
Author Keywords
Autonomous Driving, Shared Autonomous Vehicles,
Sustainability, Rebound Effects, Modal Shift
CSS Concepts
Human-centered computing~Human computer
interaction (HCI); HCI theory, concepts and models
Introduction
In the age of climate change, the pressure to create
more ecologically sustainable mobility is increasing [1].
Given this need, autonomous driving is being discussed
as a possible solution to many current traffic problems.
However, as the technology is not yet in widespread
Christina Pakusch
University of Siegen
Siegen, 57072, Germany
Christina.pakusch@uni-
siegen.de
Paul Bossauer
University of Siegen
Siegen, 57072, Germany
Paul.bossauer@uni-siegen.de
Johanna Meurer
University of Siegen
Siegen, 57072, Germany
Johanna.meurer@uni-
siegen.de
Gunnar Stevens
University of Siegen
Siegen, 57072, Germany
Gunnar.stevens@uni-
siegen.de
___________________________________________________________
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Presented at the workshop "Should I Stay or Should I Go? Automated
Vehicles in the Age of Climate Change", April 25, 2020, Honolulu, HI, USA
use, we cannot observe its effects. All we can do is try
to anticipate the effects of autonomous driving as good
as possible to guide its development towards a more
sustainable mobility.
Technical applications can never be regarded and
evaluated in isolation relating to their functionality.
Apart from their primary purpose, technical applications
are embedded in societal processes always bringing
along intended or non-intended effects on their
economical, natural and social environment [2].
Therefore, a critical assessment of the possible
consequences of AVs is needed, not to hinder that
technology, but rather to constructively support a
sustainable development of this technology [3]. Thus,
with this paper we would like to argue that HCI's
research on Autonomous Driving should not only
consider the direct effects on the individual, but also
indirect effects on a more global level such as negative
rebound effects.
HCI Research on Autonomous Vehicles
Much research has recently been conducted on AVs in
HCI, primarily focusing on the interaction and the
design of AVs. With a view to AVs, HCI studies focus on
the user experience design of (shared) AVs. One
research stream focuses on the interior design of AVs,
considering time use [4], activities that users can
imagine doing in AVs [5], and supporting productive
work as a starting point [6]. Another stream is
investigating how user interfaces ought to be designed
to serve as a communicational mean between car and
passenger [7]. Again others focus on the service design
of SAVs [8], on informing the design of interactive
communication between pedestrians and AVs [9] and
on ethical problems relevant for the design of AVs [10],
among other topics.
As such, most HCI research on AVs is so far focused on
impacts at the individual or micro level. Transportation
research, on the other hand, focuses on the macro
effects of autonomous driving. Given the current
orientations of the different research streams, we ask:
Is there a need for HCI research on AVs to consider
sustainability impacts or is HCI research leaving its
core scope?
Ecological Impacts of (Shared) Autonomous
Vehicles
To inform HCI research on what kind of consequences
of AVs might be necessary to take into account, we
give a brief summary of intended and unintended
effects.
Among transport and sustainability researchers, there
is general agreement that autonomous vehicles tend to
affect urban traffic in a harmful way when used as
private cars, but that they could considerably have a
positive impact when being used as shared autonomous
vehicles (SAVs) [1], [11]. Researchers have recently
put much effort into studies to better anticipate the
impact of SAVs on individual mobility behavior, on
transport as a whole and on transport-induced
emissions.
Experts forecast considerable potential for SAVs in
terms of ecological sustainability [12]. Just as AVs in
general, they expect SAVs to operate more efficiently
than traditional vehicles [11]. The study of Burns et al.
demonstrated that using an SAV could be 31% cheaper
The term autonomous
driving or autonomous
vehicles refers to level 5 of
the SAE International
taxonomy on driving
automation. This standard
J3016 defines six levels of
driving automation:
0: No automation
1: Driver Assistance
2: Partial Automation
3: Conditional Automation
4: High Automation
5: Full Automation
than using a private car, thus have the potential to
initiate a substantial modal shift away from the private
car towards the SAV [13]. Such studies simulating large
scale SAV fleets further revealed that SAVs have the
potential to reduce the total number of private vehicles
by up to 95% [11], [13]. These effects in combination
thus may lead to a reduced environmental impact of
traffic as fewer cars could result in a reduction of stop
and go traffic, less congestion and air pollution [1].
However, researchers also expect some downsides to
come with SAVs. Some experts expect that a future
with SAVs might cause increased vehicle kilometer
traveled leading to a potential rise in energy
consumption and emissions [1]. Some studies model
future transportation and assume that the widespread
use of AV will increase the number of car trips resulting
in 3% to 27% additional journeys [14]. Harper et al.
analyzed the effects of the availability of AVs on the
mobility of non-drivers, elderly people and people with
disabilities and concluded that an increase of 14% of
vehicle kilometer traveled can be expected, if these
groups of people drive as much as the younger people
or non-mobility restricted users [15].
Thus, given these potential chances and threats, we
ask
How can ecological and social impacts be more
systematically considered in the design of SAVs?
Such simulations are usually based on actual
transportation data. However, travel mode choices are
very complex, when new transport modes such as
private AVs or SAVs extend the range of transport
options, it will also affect the use of other transport
modes. When assessing the impacts of SAVs, besides
the desired effects, the threat of rebound effects must
also be taken into account. Presenting a comfortable
and affordable transportation mode, rebound effects
could occur in the form of more intensive use or
unwanted modal shifts towards SAVs.
Some researchers, therefore, carried out empirical user
studies with the aim of investigating positive (e.g.,
abolishing private cars) or negative (e.g., increased
vehicle kilometers) changes in mobility behavior. One
of the positive effects is that the introduction of SAVs
could lead to an abolition of cars in private households
[16] causing the overall number of vehicles (of that
sample) to drop. Another positive consequence is users
who will shift away from private cars to SAVs [17],
[18]. However, with AVs and SAVs being very
comfortable travel modes offering good time utilization
[19], studies revealed evidence that it is the public
transport users who form the majority of the future
SAV users, constituting an unintended modal shift [17],
[18]. For HCI research, it is necessary to identify and
assess possible (unintended) consequences of different
designs and developments of AVs in order to encourage
positive effects and avoid negative effects:
What are (unintended) side effects of the design
propositions at hand?
How can HCI design for AVs avoid unintended
rebound effects?
How can the interaction design of AVs encourage
behavioral changes towards a more sustainably
mobility behavior?
The Conflict of Designing for Comfortable
Use and Designing for Sustainable Mobility
The aspect of sustainability currently plays hardly any
role in HCI research on autonomous driving. Although,
aspects of social sustainability in the sense of equality
and empowerment of disadvantaged users are being
addressed [20], ecological sustainability has been
mostly neglected so far. Rather, HCI research aims to
make AVs as attractive as possible in order to create
the best possible user experience, although this might
not always be the most environmentally friendly
mobility solution. This is shown by user-centered
design studies such as those by Stevens et al., which
proposes to design AVs like tiny houses, where users
can engage in various activities such as working,
sleeping, reading, watching movies, etc. [4] or the
study by Pollmann et al., that examines how AVs
should be designed to create optimal conditions for
working in vehicles [6]. We hypothesize:
If these comfort enhancing HCI designs will be
implemented in (S)AVs, this will lead to more
intensive use of such vehicles and therefore negative
sustainability effects.
We expect and fear that such a relationship could exist,
as a comfortable design of an AV that supports the
various activities of its users will encourage intensive
use: Users will be willing to spend longer periods of
time in the car and to travel further distances by car, as
they may shift activities to the time spent travelling. In
this respect, we would like to stress the question
Will HCI Research on (S)AV (interaction) design
inevitably lead to an increased use of individual
mobility and thus to an increase in traffic problems
and emissions?
With its aim to create (S)AVs as comfortable as
possible at affordable costs, and the risk of undesirable
rebound effects, especially if users would choose
(S)AVs instead of public transportation, cycling or
walking as recent empirical studies suggest, HCI
research is facing a challenge when trying to meet both
demands. In view of the need to promote more
sustainable mobility, HCI is thus facing conflicting goals
and must take a stand accordingly in future research.
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