The Influence of Built Environment onWalking Behavior: Measurement Issues, Theoretical Considerations, Modeling Methodologies and Chinese Empirical Studies - Space-Time Integration in Geography and GIScience - page 54

van Wee 2011 ). An integrated indicator combining these D variables may increase
the comparability of the studies. Accessibility has long been a central concept in
urban planning. It is a measure of the spatial distribution of facilities adjusted for
the desire and ability of people to overcome “spatial separation” (e.g. distance or
travel time) to access a facility or activity (Handy and Niemeier 1997 ;McGinn
et al. 2007 ;Hansen 1959 ). Accordingly, desire and ability are influenced by the
importance of the trip to the user (the arrangement of that activity), attractiveness
of the facility (design), location of the facility (land use) and the user's access to
transport (Giles-Corti et al. 2005 ). Some studies adopt accessibility as an integrated
indicator. For example, Kockelman ( 1997 ) uses accessibility measures by purpose
and mode in both origin and destination zones; for non-work trips, the measures
count sales and service jobs within 30 min walking distance (Kockelman 1997 ).
Krizek ( 2003 ) adopts neighborhood accessibility measures that combine density,
land use mix, block size and regional accessibility based on gravity (Krizek 2003 ).

5.2.1.2 Subjective Measures

Most studies have found little agreement between objective and perceived measures
of environmental attributes (McCormack et al. 2008 ; Gebel et al. 2009 ;McGinn
et al. 2007 ). The studies conducted to date have provided limited guidance on the
relative effectiveness of subjectively measured attributes of the built environment in
estimating their influence on walking behavior. It has been found that definitions
of subjective measures such as accessibility to or convenience of destinations
are inconsistent across studies due to different contexts and the distinct survey
questionnaires applied to different types of walking. Further, the mechanism that
forms individual perceptions is not explicitly instructed. Unstructured questions
such as those involving the presence of destinations (e.g. shops) contribute little
to the understanding of the true nature of human perception (Moudon et al. 2006 ).
The measures employed are often the results of questions in which respondents
impose their own views on the attributes. General perceptions of a residential-based
hypothesis may not be enough; we need to know exactly what the respondents
are referring to. These differences not only hinder comparisons across studies,
but also lack instructive information for policy implications. Social psychology
theories provide hints for structured subjective measures and will be illustrated
later.

5.2.2 Measuring Walking Behavior: Objective or Self-Report?

There are two types of walking behavior: walking for transport and walking for
leisure. While the best way to measure these behaviors is still unclear and separate
measurements for the different types are still required, the importance of walking is
widely recognized (Heath et al. 2006 ).