elevated areas. Thus, drivers can
feel and even press these elevated
elements, allowing them to interact
with the infotainment system. In a
user study, Spies et al. compared a
traditional, flat touchpad and the
haptic touchpad. The results show
that the haptic touchpad reduces the
number and duration of glances to
the screen and results in less lane
deviation than the use of the traditional touchpad [ 8].
Even for traditional controls such
as buttons or dials, first concepts
propose to add more tactile feedback. Prototypes of these controls,
called adaptive control elements [ 9],
can change their shape to improve
eyes-free usage in the cockpit (see
Figure 3). These controls can be
dynamically modified by reorienting the control or certain surfaces.
Similarly, the control’s geometric
shape can be modified (e.g., height
and width change from a circular to
a square control). Finally, the surface
can be modified to transmit certain
information.
March + April 2013
interactions
Tactile Automotive User Interfaces
One further option for haptic
feedback in the car is provided by
tactile interfaces based on vibration impulses. Such interfaces are
already available, for example,
integrated into the seat or steering
wheel. These are part of advanced
driver-assistance systems and may
emit vibration impulses to inform
drivers when they leave the lane
unintentionally. So far, vibration
output is used only to alert drivers of an event. However, a few
research projects posit that vibration
feedback can communicate more
than just simple warning signals.
The navigation context seems to
be a promising application area, in
which complex information such
as distance to the next turn or
intersection could be encoded as
vibration signals. This would have
the same advantage as muting the
sometimes annoying audio output
of the navigation system (a common
practice among drivers), but would
not result in missed turns. The
vibration output can provide suffi-
cient information or may prompt the
driver to look at the display.