Respondents are then asked to indicate their experience shipping freight
between each of the origin–destination pairs in the study, across a series
of three screens (one for each corridor). For each of the three corridors,
respondents are asked to indicate whether they ship goods along the corridor,
and the frequency (if any) of shipping activity along the corridor. This information
is not only valuable for investigating variations in preferences
(for example, those with higher frequencies of shipping activity along a corridor
may have important differences in sensitivities to cost or levels-of-service
to those with lower frequencies of shipping activity), but also enables the
ensuing choice menus to focus on one specific origin–destination pair with
which the respondent has current freight experience. The specification of the
unique origin–destination pair represented within all of the choice menus for
a given respondent is made in a screen following these three corridor-centred
screens. If the respondent has experience with one origin–destination pair,
the choice menus are seeded with this pair by default; if the respondent has
experience with two to six pairs, the respondent and interviewer select one of
the pairs to seed the choice menus; this enables the interviewer to ensure
adequate responses are received across the three corridors.