Automotive User Interfaces and Interactive Vehicular Applications

Speech, buttons or both?
A comparative study of an in-car dialogue system
ABSTRACT
In the DICO project a user test was performed to evaluate
an in-vehicle dialogue system with three different modalities;
speech user interface (SUI), graphical user interface (GUI)
and multimodality (MM). Task performance, task completion
time and driving ability were measured. We found that
although the GUI was fast and easy to use, the participants
experienced that their driving ability was better when using
the SUI and multimodal interfaces, and the multimodal
interface was preferred over GUI and SUI.
Categories and Subject Descriptors
H.5.2 [Information Interfaces and presentation]: User
interfaces—Evaluation
General Terms
Design
Keywords
Evaluation, in-vehicle, dialogue system, performance, cognitive
load.
1. INTRODUCTION
This paper describes an empirical investigation of an invehicle
dialogue system comparing three different interaction
modes (voice, manual and multimodal interaction) with respect
to task performance, (self-estimated) driving ability
and task completion time. In order to let the driver keep
her hands on the steering wheel and the eyes on the road,
dialogue systems are gaining an increasing interest from the
car manufacturers. At the same time, the usage of mobile
Copyright held by author(s)
AutomotiveUI’11, November 29-December 2, 2011,
Salzburg, Austria
Adjunct Proceedings
Jessica Villing, Staffan Larsson
Department of Philosophy, Linguistics and
Theory of Science, University of Gothenburg
Olof Wijksgatan 6
Gothenburg, Sweden
{jessica, sl}@ling.gu.se
phones while driving is a much debated issue, for safety reasons.
The main objection is that the mobile phone conversation
takes the attention from the driving task, and the concern
is that the usage of in-vehicle dialogue systems would
show a similar pattern. However, since mobile phone conversations
and dialogue system interactions are very different
from each other, this type of comparison is not necessarily
very meaningful. Furthermore, the alternative to dialogue
system interaction is not no interaction, but interaction using
manual (haptic) input and graphical output (as in traditional
GUIs). To find out if a dialogue system is a reasonable
alternative to manual input we therefore wanted to compare
different user interfaces that is designed for performing the
same tasks.
The overall conclusion is that the multimodal condition gives
the same task performance as the manual condition, the
same driving ability as voice condition, and beats both with
respect to driving ability.
2. RELATED WORK
There has been a number of similar studies carried out before.
For example, the SENECA project evaluated manual
vs. speech input, when using a Driver Information System
(DIS) containing radio, CD player, telephone and navigation
[2]. 16 subjects compared a manual DIS system with a DIS
system that was equipped with a speech input system. The
findings from the study shows that a multimodal application
is preferable, that safety can be improved by using speech,
and that the drivers feel less distracted when using speech.
Another study, commissioned by Nuance and performed by
the HMI laboratory of the Technical University of Brunswick,
Germany [8], shows similar results. When comparing a manual
interface to a speech interface, it was found that using
a manual interface resulted in greater distraction and an increase
in the number of times drivers looked away from the
road. When using the manual interface the drivers rated
their driving ability as poorer, and a Lane Change Task
(LCT) showed a significant decrease in driving performance.
Medenica and Kun [5] compared interacting with a police radio
using the existing manual interface to interacting using
their Project54 speech interface, which was adapted to function
in the same way as the manual interface. The graphical
interface, unlike the SUI, resulted in a significant degradation
in driving performance.