We identified a SCE as our best approach toward capturing the key behavioural
measures that might induce freight mode shift under either carbon pricing or
the introduction of new short sea shipping services in Australia. Fundamentally,
SCEs enable analysts to quantify preferences under hypothetical mixes of
alternatives and specifications of those alternatives (that is, attribute levels) that
are not present in the market. This is critical in this application, given a lack of
both price signals relating to carbon emissions abatement (for example, carbon
taxes or carbon prices) and short sea shipping alternatives for the corridors
in consideration within the study. We further identified a computer-based
(with personal interview) survey instrument as our preferred SCE approach,
due to the ability of a computer-based survey both to allow choice menus to be
tailored to respondents’ experience with respect to prices and transit times, and
to capture and store survey data accurately and efficiently. The personal
interview component is strongly preferred due to the need to ensure that
respondents can make informed choices within an instrument and series of
tasks that may be unfamiliar to them.
Feo et al (2011) offer a contemporary confirmation of the merit of such an
approach, through a stated choice study of preferences for trucking versus short
sea shipping in the Spanish market, comparing preferences for high-value cargo
versus low-value cargo within individual modes. Our study follows the behavioural
framework of Brooks and Trifts (2008), in which mode choice is not
a binary decision, but rather involves the issue of proportional allocation across
modal alternatives. Consistent with Feo et al (2011) characteristics of the
cargo are tested as key influences on preferences for modal alternatives