Automotive User Interfaces and Interactive Vehicular Applications

However, all of the above mentioned studies compare two interaction
modes, whereas the current study compares three:
GUI, SUI and multimodal interaction. Furthermore, common
to all earlier studies known to the present authors is the
fact that the interactional capabilities offered in the evaluated
modalities originate from different systems. Even if
the systems have been adapted to make sure that they function
in the same way, they are still different system. This
makes it hard to determine exactly how they differ, and how
much influence the design of the interfaces in the respective
modalities has on the result. In general, it may be difficult
to specify exactly what it means to say that a GUI and a
SUI or multimodal interface function in the same way. We
believe that the implementation of integrated multimodality
(see below) in the DICO system used in the present study
guarantees functional similarity in a principled way, while
maintaining the advantages of the respective modalities.
3. BACKGROUND
3.1 The GoDiS dialogue system
The applications used in this study are developed using the
dialogue system GoDiS [3]. GoDiS is implemented using
TrindiKit [6]. General dialogue management issues such
as feedback, grounding, question accommodation and task
switching are handled by the application independent dialogue
manager. Re-using these technologies in new applications
enables rapid prototyping of advanced dialogue
applications. GoDiS has been adapted to several different
dialogue types, domains and languages.
3.2 The DICO project
The DICO project aimed to develop a proof-of-concept demo
system, showing how a spoken dialogue system can be an
aid for drivers. The Dico application was developed using
GoDiS, and implements integrated multimodality. This
means on the system output side that all modalities convey
all information independently, without support from
the other modalities. On the system input side, the user
can freely choose either one of the possible input modalities
at any time to interact with the dialogue system, since all
modalities allow control of all functionality. The advantage
of this approach is that the user does not have to rely on
one single modality. If, for example, speech is unsuitable
at the moment (e.g. due to a noisy environment) the user
can choose another modality and still have access to all functionality.
The user can also choose the modality that is most
convenient for each action. It might, for example, be easier
to speak a phone number instead of enter it manually on a
keyboard while driving, and it might be easier to choose an
item from a multi-choice list by pushing a button instead of
speaking it.
For the study described in this paper we took advantage of
the integrated approach and created three test conditions
where the unwanted modality was temporarily removed:
1. SUI (Speech User Interface) interaction
• speech only for input
• speech and screen for output 1
1 This means that the SUI output is not completely uni-
2. GUI (Graphical User Interface) interaction
• buttons for input
• screen for output
3. Multimodal interaction
• speech and buttons for input
• speech and screen for output
The Dico application contains a telephone domain and a domain
for logistic tasks. When using the telephone domain it
is possible to make phone calls by dialling a phone number
or a contact in the phone book, and to add or delete a contact.
The logistics domain is an aid for a commercial driver
where it is possible to look at orders to find out where goods
should be picked up, accept/reject orders, get information
about driving time to find out when it is necessary to get a
break, and to look at a map to see the route or to find out
where nearby colleagues are located.
The setup of the keypad used for the manual input was
similar to a computer keypad, see Figure 1. There were
buttons for all figures, arrows to navigate up and down in a
menu, an erase and an enter button and also preset buttons
to choose domain (telephone or logistics).
Figure 1: Keypad used for manual input.
One area where the present study differs from previous work
is in the use of the same dialogue manager for all three
modalitity variants. The obvious advantage is that the results
will not be affected by, for example, differences in the
design of the menu structure or system instructions. To the
authors knowledge, there are no previous evaluations of different
interfaces using the same dialogue manager.
4. METHOD
There were ten subjects participating in the study, 6 females
and 4 males, ages 27 to 53. None of them had any experience
of controlling devices in the car using voice control or
dialogue systems, although one of them had experience from
using voice to control functions in a mobile phone.
The trials took place on a two-lane country road with several
traffic lights and roundabouts. The traffic load was fairly
moderate, with approximately 3 cars per minute encontered
in the opposite lane. The participants drove a Volvo XC90
guided by the test leader along a predefined route. The
entire route took about 30 minutes, which means that each
test condition lasted about 10 minutes. There were four
tasks to perform, two for each application:
modal; the reason for this is that it was necessary to show
a map on the screen to be able to perform one of the tasks.