Automotive User Interfaces and Interactive Vehicular Applications

integrating past, existing and future mobile devices into
cars and at the same time offers adequate mechanisms to
adjust applications at runtime to meet automotive
requirements.
POSSIBLE COUNTERCLAIMS
A high-level platform running 3 rd party software might
not fulfill legal requirements for IVI systems [4].
This claim is certainly true for all solutions that are capable
of integrating 3 rd party applications into the head unit‟s
HMI. While it might always be necessary to test and
approve foreign applications for in-vehicle use, high-level
applications offer several advantages. They are constrained
to a limited set of features of an approved application
programming interface (API) and can only use approved
functions to interact with the driver. We are convinced that
high-level applications offer the best opportunities for
automated tests and automated adjustments towards a target
IVI system, as described later.
A common platform makes it difficult for OEMs to
differentiate their products from each other [2].
Especially the HMI is known to be relevant for
differentiation of IVI systems [1].
The same is true for Smartphones, nevertheless vendors
cooperate to take advantage of economies of scale. In the
near future, cars might as well be valued by buyers by the
number of popular 3 rd party applications they support. As
described later, we believe that compatibility to a broad
range of other platforms is important in order to establish a
platform attractive to a reasonable number of developers.
Nevertheless, a high-level platform also offers advantages
for differentiation as described in the paragraph „Advances
for car specific Adoption‟.
A high-level platform drastically reduces the number
of available applications and is not capable of running
or displaying legacy Smartphone applications [4].
We are convinced that this is not a limitation but an
advantage of high-level platforms. While other platforms
need to deal with the difficult problem to filter out all
features that are inappropriate while driving, a high-level
platform restricts application components to approved
features.
It is insecure to execute 3 rd party software in cars [4].
We agree, that it will still remain necessary to test and
approve 3 rd party software in order to allow execution in an
IVI system. Nevertheless, high-level Web Applications are
executed in a browser sandbox and thereby divided from
the native IVI system.
OUR SOLUTION FOR DEVICE INTEGRATION
Our platform [5] [6] is based on a Web Application
Framework as common middleware across multiple mobile
and automotive platforms. A prototype we developed
targets Google Android as mobile platform and a research
IVI system, but our software might be easily transferred to
other platforms as well. Figure 1 gives an overview of our
software architecture. Web Applications are transmitted to
the IVI system so that it can adapt them and control their
execution. In comparison to standard Web Browsers, the
Web Application Framework provides additional software
interfaces to Web Applications that connects them with the
underlying platform.
Mobile
Web
Application
Framework
IVI system
Web Application Framework
Web Application
Controls
Sensors
Figure 1: Distributed Web Application Framework
We extended the open source Web Application Framework
„PhoneGap‟ [7] by methods for accessing vehicle specific
controls and sensors. Additionally, we added remote
procedure calls to the framework in order to communicate
with remote devices. Figure 2 shows a Messaging Web
Application on a Smartphone and on an IVI system. When
executed in the IVI system, styling and sizes of User
Interface elements of the Messaging Application are
adapted.
Figure 2: Messaging Web Application
PRODUCT LIFETIME ISSUES
Cars tend to have much longer life cycles than mobile
devices. Therefore, it is very important to provide a
solution that is capable of interconnecting future mobile
devices with unknown features. Legacy Smartphone
applications might become obsolete with the next version
of their platform. Experiences with Web Technologies are
more promising: While the future impact of certain mobile
platforms is difficult to predict, Web Technologies have
shown to stay stable over years and are known to be
backwards compatible to a high degree.
COMPATIBILITY TO OTHER MOBILE PLATFORMS
Compared to Smartphone application development, IVI is a
niche market. The number of cars produced by a single
OEM comes not even close to the number of Smartphones
shipped by huge Smartphone vendors. In 2010, 1.6 Billion
Mobile phones were shipped (of which were approx. 300
Mio. Smartphones) [9]. In the same year, OEMs produced
about 78 Million vehicles [8]. Table 1 shows the annual
production lots of the top five car manufacturers in 2010
and the number of Smartphones shipped for the top five
Smartphone platforms in the same year. According to