Factors influencing car use for commuting and the intention to reduce it: A question of self-interest or morality?

Abstract

Car use for commuting contributes to various environmental and traffic problems, such as pollution and congestion. Policies aimed at reducing commuter car use will be more effective when they target important determinants of car use and willingness to reduce it. This study examined whether variables reflecting self-interest (from the theory of planned behavior [Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhl & J. Beckmann (Eds.), Action control: From cognition to behavior (pp. 11–39). Berlin: Springer]) and variables reflecting moral considerations (from the norm-activation model [Schwartz, S. H. (1977). Normative influences on altruism. In L. Berkowitz (Ed.). Advances in experimental social psychology (Vol. 10, pp. 221–279). New York: Academic Press]) were able to explain self-reported car use for commuting and intentions to reduce it in a sample of Canadian office workers. Car use for commuting was mostly explained by variables related to individual outcomes (perceived behavioral control and attitudes) whereas the intention to reduce car use was mostly explained by variables related to morality (personal norms). The study also found that perceived behavioral control moderated the relation between personal norms and behavioral intentions: stronger personal norms were associated with stronger behavioral intentions, but only when perceived behavioral control was low. Some issues evoked by these results are discussed.

Introduction

Vehicle transport, although it serves many societal functions as well, also contributes to various problems, such as environmental pollution and traffic congestion. Of all modes of transportation, cars account for the largest proportion of emissions of polluting substances, such as CO₂, thereby contributing to global warming (OECD, 2002). For example, greenhouse gas emissions for urban travel in Canada in 1997 were 215 g per passenger-kilometer for a car or a light truck, 77 g for urban transit, 26 g for intercity bus travel, and, of course, 0 g for walking or cycling (Transport Canada, 2008). In OECD countries, commuting accounts for an estimated 25% of household travel (OECD, 2002). Despite efforts at reducing the environmental impact of cars by means of technological innovations (e.g. more efficient engines, hybrid fuel systems, and fuel cell technology), various trends tend to nullify this positive effect, such as increased car ownership, and increased frequency of car use. Therefore, apart from technological innovations, travel demand management policies are needed as well. This implies that factors related to car use behavior and intentions to reduce it are important to consider.

Commuting to work is one such behavior. Because it occurs on a regular basis, and within a fixed time frame, viable alternatives are more likely to exist than for other types of car trips. For instance, car pooling and more frequent public transport during rush hours can facilitate the use of alternative modes of transport to get to work. Attempts to encourage commuters to reduce car use will be more effective when they address its behavioral antecedents.

This study examines which variables underlie self-reported car use for commuting and the intention to reduce it. More specifically, variables reflecting self-interest (i.e. from the theory of planned behavior (Ajzen, 1991)) and variables reflecting moral considerations (stemming from the norm-activation model; Schwartz, 1977) are compared as explanations for car use for commuting and the intention to reduce it. Also, interaction effects are explored between ‘self-interest’ variables and moral considerations. This study builds on previous work in the field with student samples (e.g. Bamberg & Schmidt, 2003) by studying a sample of government employees (i.e. working for several Canadian Ministries).

To understand why commuters drive to work instead of using more environmentally friendly modes of transport, it is necessary to consider the behavioral antecedents of car use for commuting and the intention to reduce it. Two approaches to explaining pro-environmental behavior are often used (Bonnes & Bonaiuto, 2002). On the one hand, rational choice theories (e.g. Ajzen’s (1985) theory of planned behavior; TPB) consider (pro-environmental) behavior to be a result of individual cost-benefit analyses. Other frameworks assume that moral considerations are at the basis of pro-environmental behavior (e.g. Schwartz’ (1977) norm-activation model of altruism; NAM).

The theory of planned behavior (Ajzen, 1985, Ajzen and Fishbein, 1980) assumes that behavior is determined by the intention to perform it. In turn, behavioral intentions are assumed to be determined by attitudes, subjective norms and perceived behavioral control. Attitudes in this case refer to the degree to which a person holds a favorable or an unfavorable evaluation of the idea of commuting by car. Subjective norms refer to perceived social pressure to perform or not to perform a behavior, and an individual’s motivations to comply to such social pressures. In other words, it refers to an individual’s perception of the extent to which important others would approve or disapprove of a given behavior, in this case, using a car for commuting. Finally, perceived behavioral control is the perceived ease or difficulty of engaging in a behavior, for example driving to work or using alternative modes of getting to work.

The TPB has been used to explain a wide array of behaviors, such as weight loss and smoking cessation (see Armitage and Conner, 2001, Conner and Armitage, 1998, Ajzen, 1991, for reviews). It has also been applied in the transport and environmental psychology field (e.g. Bamberg and Schmidt, 2003, Gardner and Abraham, 2008, Heath and Gifford, 2002). For instance, Heath and Gifford (2002) found that among university students, attitudes, subjective norm and perceived behavioral control were significantly (positively) related to the intention to use the bus. In turn, intentions to use the bus was significantly positively related to reported bus use (which was measured retrospectively). Harland, Staats, and Wilke (1999) also used a retrospective measure of car use and they found that attitude and perceived behavioral control were positively related to car use in a sample of households. In addition, the power of TPB in explaining car use for short trips could be improved significantly by adding the concept of personal norms. Bamberg and Schmidt (2003) found that TPB variables significantly predicted the intention to use a car in a sample of university students, and that these intentions significantly predicted future car use.

The norm-activation model (NAM) takes a somewhat different perspective by focusing on altruistic behavior, that is to say, behavior that implies giving up personal interests for the benefit of others (Schwartz, 1977, Schwartz and Howard, 1981). Pro-environmental behavior may be considered as a form of altruistic behavior, because it entails giving up personal benefits for the sake of the environment. For instance, deciding to commute to work by bus instead of by car out of environmental concerns probably involves less convenience (more walking, to the bus stop) and freedom (less choice about when to leave home and work, to fit the bus schedule), and may entail longer travel times.

Moral considerations play an important role here, as engagement in pro-environmental behavior (and pro-environmental intentions) is assumed to be determined by the extent to which people feel a personal obligation to do so (reflected in personal norms). Behavior in accordance with these personal norms may lead to a sense of pride, whilst feelings of guilt may arise when one’s behavior is not in accordance with one’s personal norms. Two additional factors are involved in this norm-activation process. First, individuals must realize the consequences of their behavior for the environment (referred to as awareness of consequences). Those who believe that car use has negative environmental consequences are assumed to feel a stronger moral obligation to reduce their car use than those who do not recognize these negative consequences. Second, individuals must feel personally responsible for the behavioral consequences (ascription of responsibility) before they will engage in pro-environmental behavior. Those who assume responsibility for the problems resulting from car use will feel more obliged to help solve these problems by reducing their car use than those who do not assume this responsibility.

Furthermore, one of the assumptions in the NAM is that activated personal norms result in altruistic behavior when no barriers are perceived and no high costs are involved: “Once potentially helpful actions are recognized, internalized values become relevant only for those actions a person feels able to execute” (Schwartz & Howard, 1981, p. 197). Thus, following from this, perceived behavioral control may moderate the relationship between personal norms and behavior (and intentions). The norm-activation model has been successfully applied to a wide array of pro-environmental behaviors; including recycling (Guagnano et al., 1995, Hopper and Nielsen, 1991), political action to support the environment (Stern, Dietz, & Kalof, 1993), and car use (Bamberg & Schmidt, 2003). However, studies testing the NAM have not included perceived behavioral control, nor examined its possible moderating effect.

The present study examines which set of variables (related to self-interest or moral considerations) has the greatest explanatory power in relation to car use for commuting and the intention to reduce it. Because the theory of planned behavior is expected to be especially relevant for explaining behavior when high personal costs (in terms of time, effort, convenience, etc.) are involved (such as car use and intention to reduce it, see Lindenberg & Steg, 2007), it is expected that self-interest variables will be better suited for this purpose. In particular, we hypothesize that more positive attitudes towards car use and stronger subjective norms in favor of car use will be positively related to commuter car use and negatively related to the intention to reduce it, and that higher levels of perceived behavioral control to reduce car use are negatively related to commuter car use, and positively to behavioral intentions. We expect that variables reflecting moral considerations will be less suitable for explaining car use for commuting and intention to reduce it (cf. Bamberg & Schmidt, 2003). Finally, we expect that extending the NAM with perceived behavioral control will add significantly to the explanation of car use and intention to reduce it, and that it will moderate the relationship between personal norms and behavior and personal norms and behavioral intention, as suggested by Schwartz and Howard (1981) in such a way that the relationships between personal norms and behavior and behavioral intention will be stronger when levels of perceived behavioral control are high.