On-the-Move and in Your Car - Human-Computer Interaction and Innovation in Handheld, Mobile and Wearable Technologies - page 62

and collision avoidance (the vehicle auto-
matically responds to an emergency situa-
tion). Clearly, such systems fundamentally
change the nature of what we consider to
be 'driving'.

Inevitably, the introduction of new technolo-
gies into the driving context will have a consid-
erable impact across all three levels. As a result,
there are many human-focused issues that must be
considered in the design and evaluation process for
in-car computing systems. To provide structure to
a discussion of these issues, two overall scenarios
are envisaged which may arise from poor design
and/or implementation of the technology.

It is important to note that there is a third cat-
egory of in-car computing system, those which do
not provide any functionality to support the driving
task. These systems are an important consideration
though, as they can negatively influence safety,
particularly through the potential for distraction
(Young, Regan and Hammer, 2003). Such systems
may aim to enhance work-oriented productivity
whilst driving (e.g. mobile phones, email/internet
access) or be primarily conceived for entertain-
ment/comfort purposes (e.g. music/DVD players,
games). Moreover, they may be designed for
dedicated use in a vehicle or for operation in a
range of different contexts, e.g. as a driver and
as a pedestrian (often termed nomadic devices).

• Overload: Many of these systems (par-
ticularly those providing novel types of in-
formation and/or interactions) lead to situ-
ations in which a driver must divide their
attention between core driving tasks (e.g.
watching out for hazards) and secondary
system tasks (e.g. inputting information).
Furthermore, systems may provide exces-
sive information in an inappropriate way
leading to high levels of mental workload,
stress and frustration. Such issues often
manifest themselves as distraction to the
driver (biomechanical, visual, auditory
and/or cognitive).
• Underload: Control-based systems clearly
automate certain aspects of driving, trans-
ferring certain responsibilities from op-
erator to computer (e.g. staying in lane),
whilst potentially providing new tasks for
the driver (e.g. monitoring system perfor-
mance). Automation is a fundamental hu-
man factors topic with a considerable re-
search literature (see Wickens et al., 2004).
Key concerns in this context relate to the
potential for a driver exhibiting reduced
situational awareness (e.g. for other road
users), negative behavioural adaptation
(e.g. by taking greater risks) and de-skill-
ing (e.g. driver not able to resume control
in the event of system failure).

OVERALL HUMAN
FACTORS ISSUES

Driving is a complex task involving a large number
of subtasks that can be conceptualised as exist-
ing within three levels of an overall hierarchical
structure (Michon, 1985):

• Strategic tasks (highest level global travel
decisions—e.g. which car to take, which
route to take);
• Tactical tasks (making concrete manoeu-
vres requiring interaction with other road
users -e.g. changing lane, turning at a
roundabout);
• Operational tasks (motor execution of
tasks planned at higher levels—e.g. turn-
ing steering wheel, pressing brake).