Psychological and contextual influences on travel mode choice for commuting
Travel behaviour - especially car use - is of concern because it contributes to
environmental problems such as climate change. Focusing on commuting, this thesis
aimed to explain people's travel mode decisions and what might motivate drivers to
switch modes. The literature shows that - as in the wider field of environmentallysignificant
behaviour - Schwartz's norm-activation theory (NAT) and Ajzen's theory of
planned behaviour (TPB) are predominant in travel psychology. Research undertaken
for this thesis was based on these theories.
Study 1 used logistic regression (n = 312) to test NAT and the TPB's ability to
explain drivers' intentions to maintain or reduce their car use for commuting to De
Montfort University (DMU). A model using variables from both theories was also tested,
as was a model that added contextual variables to these psychological constructs. The
model including contextual variables had the greatest predictive power (shown by Rl
values). There were interactions between several predictor variables. Most notably, the
influence of altruistic (pro-environmental) motives on intentions was moderated by
perceived control over commuting mode choice and by contextual factors including
bicycle ownership, carriage of passengers and journey time.
In study 2,24 semi-structured interviews were undertaken with commuters to DMU.
Using discourse analytic techniques, the prevalent stances on car use and use of other
modes for travel to work were identified. Many echoed NAT and TPB constructs (e.g.
moral motives, perceived control over modal choice), underlining these theories'
applicability to commuting. However, other stances were also evident, most notably
affective motives and habits as reasons for commuting mode decisions. People drew
on various combinations of these discourses to explain their commuting behaviour.
The thesis proposes a new model of commuting mode choice and suggests guidelines
for interventions designed to encourage drivers to use alternative modes. However, it is
stressed that reliance on attitude-behaviour research alone may ignore wider sociocultural
influences on travel behaviour. Suggestions are made regarding theoretical
perspectives and methods that may help in understanding these forces and a case is
made for mixed-method research as the way ahead for travel psychology.