Automotive User Interfaces and Interactive Vehicular Applications

Investigating the Usage of Multifunctional Rotary Knobs in
the Center Stack with a Contextual Inquiry
Katja Neureiter, Alexander Meschtscherjakov, David Wilfinger, Manfred Tscheligi
Christian Doppler Laboratory “Contextual Interfaces”
HCI&Usability Unit, ICT&S Center, Universität Salzburg
Sigmund-Haffner-Gasse 18, 5020 Salzburg, Austria
firstname.lastname@sbg.ac.at
ABSTRACT
In this paper, we describe the setup and selected results of an insitu
study, aiming at investigating the usage of In-Vehicle
Information Systems (IVIS) in the car. Thereby we focus on three
commercial systems that combine a multifunctional rotary knob
and an LCD in the center stack (Audi RNS-E, Audi MMI, BMW
iDrive). In order to investigate tertiary tasks with a special focus
on context and user experience factors we performed a Contextual
Inquiry. More than 15 different tasks were identified concerning
the operation of the radio, the navigation system and the
telephone. Our results demonstrate that using an IVIS was
especially distracting in rapidly changing situations. Comfort and
safety, which are relevant user experience factors in this study,
occurred mainly in connection with the operation of the
navigation system.
Categories and Subject Descriptors
H.5.2 [Information Interfaces and Presentation]: User
Interfaces – Input devices and strategies, theory and methods
General Terms
Human Factors
Keywords
HMI, contextual inquiry, automotive, study, input modality, IVIS
1. INTRODUCTION
Modern cars provide a multitude of input and output modalities to
assist and support the driver regarding primary, secondary and
tertiary tasks. Tönnis et al. [5] describe primary tasks as
maneuvering the vehicle, secondary tasks as mandatory functions
to increase safety (e.g. setting turning signals) and tertiary tasks
covering entertainment and information functionality. Especially
for tertiary devices the automotive industry has chosen different
interaction modalities. Recently a shift towards multifunctional
devices can be observed [5]. They allow centralized access to all
tertiary functions, while providing a high level of ergonomics,
e.g., Audi’s Multi Media Interface (MMI) (www.audi.com) and
BMW’s iDrive (www.bmw.com). The systems provide one
central controller (rotary knob) positioned in the horizontal center
stack.
Copyright held by author(s)
AutomotiveUI’11, November 29 – December 2, 2011, Salzburg, Austria.
Adjunct Proceedings
- 19 -
In order to investigate the actual usage of In-Vehicle Information
Systems (IVIS) we performed an adapted version of Beyer and
Hotzblatt’s [1] Contextual Inquiry (CI). Three main research
questions were defined:
• What kind of tasks is performed with the
multifunctional rotary knob and how do participants use
the system in order to carry out these tasks? (RQ1)
• To what extent do interactions with the system have an
influence on the primary task of driving? (RQ2)
• What are the users’ experiences and requirements
towards the system? (RQ3)
2. BACKGROUND AND RELATED WORK
So far, only a few qualitative in-situ studies have been conducted
within the automotive area. Esbjörnsson et al. [2] conducted an
ethnographic study in order to investigate naturally occurring
mobile phone use in traffic. Their results show how drivers adapt
driving behavior and mobile phone usage to match each other.
Hjälmdahl and Várhelyi [4] indicate that in-car observation with
human observers in the car is a reliable and valid method to study
driver behavior with specific focus on traffic safety. Gellatly et al.
[3] adopted the contextual design process, aiming to investigate
driver’s interactions with entertainment, communication,
navigation and information systems in their vehicles. The authors
identified a row of barriers in and around the car, which distract
the driver from operating the car safely.
Similar to Gellatly et al. [3] we conducted a CI to explore the use
of IVIS. The benefit of the CI, in contrast to a simple interview or
questionnaire, is that the inquiry takes place in the users’ natural
environment. This approach allowed us to gain a deeper
understanding of the users’ actions. [1].
3. STUDY SETUP
Ten people participated in the study, aged between 24 and 63
years (average age: 39,6 years). Nine participants were male and
only one was female, due to the fact that only two women
responded to our announcement and only one decided to
participate in the study. The cars in which the observation took
place were equipped with one of the following three systems: The
BMW iDrive, the Audi MMI or the RNS-E System from Audi (a
previous model of the MMI system). Additionally to the central
rotary knob all cars had control buttons on the multifunctional
steering wheel. The study took place over a period of six weeks.
The route for the rides was determined by the driver themselves in
order to obtain “natural” driving conditions. One ride took one
hour on average. Following the CI method, the researcher (sitting