This thesis is concerned with the problem of designing Mobile Location Services (MLS) - also
commonly termed Location-Based Services - that meet user needs. MLS are applications that
users access via a portable device such as a mobile phone. They provide services (i.e.
information or other functionality) to end-users based on knowledge of the location of
individuals and other entities within the environment. The market failure of many mobile
services, including MLS, has been attributed in part to failing to provide `value' to the end
user. This thesis reviews different theoretical approaches to help understand the notion of
`value', and how value may be used to inform design (Chapter 2). Research methods are also
discussed, including the particular challenges with doing `mobile' research (Chapter 3).
A survey of UK consumers( Chapter4 ) demonstratesa current lack of use, and lack of
awarenesso f most forms of MLS in the UK. llowever, overall positive attitudes,a nd a range
of behavioural and demographic data, suggest that MLS have the potential to be successful if
they can be designed to meet user needs. A qualitative study of users' travelling behaviour
(Chapter 5) then demonstrates how effective mobile information delivery can provide
considerable value within a dynamic, uncertain and location-varying environment. This added
value is highly dependent on contextual and situated factors, including existing information
sources, variances in possible outcomes and the intrinsic qualities of information provision.
The thesis then focuses on a particular application domain for MLS - drivers navigating in an unfamiliar environment. A literature review (Chapter 6) investigates how drivers navigate, and
what their information needs are. Three experimental studies (Chapters 7 to 9) then investigate what information adds value within a navigation context, the impact of contextual influences on driving and navigation performance, and the impact of the quality of the navigation cue on task performance. Good landmarks (such as traffic lights) are shown to add value for drivers
navigating an unfamiliar route, depending on the context at particular manoeuvres. This thesis discusses( Chapter 10) how a multi-disciplinary perspectivec an help maximise the acceptance and effectiveness of MLS. 'Value' can be used to design specific services for users, based on offering new freedoms to the individual within a mobile context, employing time and location sensitivity to maximise relevance, taking into account user knowledge, existing information sources and contextual factors, and ensuring impact on real-world outcomes. In conclusion (Chapter 11), specific contributions and avenues for future work are highlighted.