This study shows that the combination of RBV and ST presents a better explanation as to why companies reduce transportation emissions than either of them do separately. By combining the two theories it is possible to differentiate between how stakeholder pressure and company strategy influence intents to green transportation. This finding confirms the view of [41] Sarkis et al. (2011) and [11] Carter and Rogers (2008) that RBV and ST are complementary theories in SCM research. It further supports [24] Hart's (1995) view that factors related to the natural environment are internalised in RBV. Both company-internal motives from RBV and external drivers from ST have a role in explaining a company's intent to reduce transportation emissions, but our findings show that their roles differ: external drivers lead to a reduction of transportation emissions to a predetermined point (the actual requirement) for all companies, while internal motives differ between companies.
A factor analysis provided further details on the differentiation between stakeholder pressure and company strategy. Three factors represent motives and drivers for greening transportation: external requirements, economic motives and image motives. The effect of external requirements on intended emissions reductions did not differ significantly across clusters of companies. Our conclusion is, again, that companies face similar requirements - which they fulfil but do not necessarily exceed. Nonetheless, stakeholder pressure has a role in greening transportation. It sets minimal levels that elevate the performance of a group of companies in an industry or a country, which in turn can become more competitive - at least when compared to the same industry in other countries where requirements may differ.
The effect of economic and image motives on the intended reduction of transportation emissions differed across clusters of companies. Companies with a strategy that led to either economic or image motives had similar intent to reduce transportation emissions, but companies that combined these motives showed the highest intent to reduce transportation emissions. Since motives are derived from RBV, the results indicate that a company's strategy influences its intent to green transportation. This implies that green transportation is not only a logistics or SCM consideration, particularly as the main reasons (e.g. environmental employer, social responsibility and marketing advantage) appear to be outside the logistics domain. Our study indicates that greening transportation should imbue an entire organisation in the overall corporate strategy. This is supported in a study by [3] Banerjee et al. (2003) who emphasise that top management has a key role for pointing out the direction for greening transportation.
The three factors stem from eight motives/drivers. Related to the image factor, it is worth noting that being seen as an environmental employer and showing social responsibility were the strongest motives. In the economic motive factor, obtaining long-term competitive advantage was strong, while short-term company profitability was the least important motive, even though the survey was conducted among public companies. Our results show that positive impacts on performance are expected in the long run rather than in the short term. This seems to support that reducing transportation emissions is not primarily a decision based on improving efficiency in logistics or transportation, but rather a part of a company's strategy to improve their image and long-term competitive advantage. This would help explain why companies have not implemented environmental practices to the extent that is discussed as economic potential in the literature, which often relates to concurrent economic and environmental benefits of environmental practices ([39] Rao and Holt, 2005). All dimensions of the external requirements were seen as having lower importance. However, we have not investigated if customers and owners have indirect roles, such as if customers prefer to do business with a company that shows social sustainability or if owners want the company to be seen as an environmental employer to attract future employees. Such potential linkages need further research.
In line with the discussion that greening transportation is more than just an issue for logistics, our study showed that LRC has only a limited impact on drivers/motives: neither logistics structures (only two out of 48 tests showed significant correlations) nor control over logistics operations seem to affect drivers and motives. Previous research has shown that changing logistics structures can reduce the environmental impact of logistics ([1] Aronsson and Huge Brodin, 2006), but our findings show that the motives to change are not related to LRC. For instance, the motives do not seem to be affected by the geographical spread of plants, warehouses or suppliers. This is quite surprising. A potential explanation is that greening considerations rather stem from the overall strategy of a company than from logistics as discussed above. Our study supports this suggestion since two of the most important motives for reducing transportation emissions are being seen as an environmental employer and showing social responsibility. It should also be noted that all companies in the study are in freight transportation-intensive industries. This means that they have a basic need to reduce transportation emissions. As can be seen in Table VI [Figure omitted. See Article Image.], many actions can be taken to do so. Irrespective of LRC, some kind of action can be taken to reduce transportation emissions for companies that are motivated. For companies in other less transportation-intensive industries, LRC may play a different role as the levels of emissions might vary to a greater extent between companies. These potential explanations require further research.