1. Introduction and Theoretical Background
Consumer decision-making processes have been in the scope of scientific and academic interest since the 1960s. [1
]. The research results in this area help understand the markets and the mechanisms of the behavior of different market entities (sellers, consumers, competitors). Making purchasing decisions is a complex cognitive process involving many factors, among which the main role is played by searching for and processing information. Studies show [4
] that a significant proportion of purchases made by consumers are planned behaviors. With the development of information technology and easier access to information, a significant proportion of customers have a greater knowledge of products. At the same time, the excess of information associated with the large number of products available on the market often makes consumers feel confused and impedes decision-making. According to [7
], the key process behind making purchasing decisions is the integration process, in which the acquired knowledge is combined to assess two or more alternative behaviors and choose one of them. Consumer engagement in purchasing decisions is also a direct result of the reaction to marketing and advertising stimuli [8
]. Highly engaged consumers are more interested in the product and are more likely to buy it. Companies have long been analyzing buyer decision-making processes to find answers to the most basic questions such as what, how, how much, when, why, and where the consumers buy [9
In recent years, dramatic changes in the global state of the environment, increasing pollution as well as environmental health aspects have become one of the most important contemporary social problems. The growing ecological awareness is the main driving force for introducing various activities directed towards the prevention of adverse environmental changes [10
]. Moreover, relatively recently in both developed and developing countries, consumer care for the natural environment has become a vital part of purchasing processes; and consequently, has led to changes in many aspects of the functioning of enterprises, their marketing policies, and business strategies [11
]. Enterprises that introduce environmentally friendly products typically achieve increased sales [12
], a higher level of employee engagement [14
], greater customer satisfaction [11
], and improved company brand image [16
]. According to one definition, an environmentally friendly product is “a product that has been manufactured using ingredients that are free of toxic substances and following environmentally friendly procedures, and which as such is certified by a recognized organization” [18
]. Consumers are increasingly making their buying decisions taking into account the principles of sustainable development, as well as being aware of the consequences of the impact of their decisions on their own health and the natural environment. That is why they have begun to turn to companies that offer environmentally friendly products and services [19
], increasingly preferring sustainable alternatives. This strongly motivates companies to offer environmentally friendly goods, which has lately become almost a matter of surviving on the market [21
An important source of problems with the state of the natural environment is the intense development of various branches of industry (the automotive industry included), which is associated with an increase in the pollution of the environment by oil and petroleum products [22
]. Engine oils belong to the class of products that pose an environmental threat throughout their entire life cycle. That is why, eco-friendly engine oil should be such from the very design stage through production, storage, transport, use, to the end-of-life management. One of the most important issues concerning the rapid development of the automotive industry is the high proportion of lubricating oils lost in the environment. Lubricating oils are used primarily to reduce friction between moving machine parts, minimize their wear, improve efficiency, and save fuel and energy. During operation, lubricating oils are contaminated and gradually degraded, which means that they lose their useful properties and should be replaced. Used oils become waste oils and are classified as hazardous waste [24
]. However, waste oils are not only generated by various industries but by road, air and sea transport as well. In this context, the automotive sector is particularly burdensome for the environment, which through a continuous increase in the number of vehicles leads to greater consumption of lubricating oils. It is estimated that about 56% of the total demand for lubricating oils comes from the automotive sector. Yet, not all engine oils are recovered after their service life, as about 50% of the oil used in engines is lost as a result of evaporation or combustion [25
]. It is also worth noting that some of the oil may remain on the walls of the packaging and it can be thus introduced directly into the environment with it. The remaining part of the oil is collected at the decommissioning stage and becomes waste oil. Waste oils are collected mainly in car service stations or private (residential) garages during an oil change. Considering the environmental protection, the replacement of engine oil in professional garages or car service stations is much more advantageous because it ensures a correct and controlled collection as well as waste management. This is a particularly important issue in developing countries, which usually do not have adequate procedures for the disposal and recycling of waste oils [26
]. However, it cannot be said that the problem has been entirely resolved in developed countries either. In Europe, waste oils are the largest stream of liquid hazardous waste [28
]; whereas, in the US, less than 60% of waste oils are recycled [29
]. An oil change performed in a private garage setting may lead to improper management. If engine oil is stored in the user’s own garage for a longer period of time and in an unprotected manner; if it is poured into the storm sewer [30
], directly into soil or wastewater sewers [32
], it may cause significant pollution of groundwater and soil [10
]. When engine oil is spilled, it migrates down through the soil, reaching groundwater, and then spreads sideways because of capillary forces and soil heterogeneity. During a non-professional oil change, uncontrolled incineration accompanied by metal and PAH (polycyclic aromatic hydrocarbons) emissions may also take place [33
], which are then generally adsorbed by airborne dust to eventually settle in soil and water.
Contaminants found in waste oils have an adverse effect on both human health and the environment, and the degree of impact on the environment depends on three basic factors: the chemical composition of the oil, the conditions of its operation in the machine, and the methods of its management [35
]. The presence of degraded additives, waste and degradation by-products in waste oils translates into an increase in their toxicity and harmfulness to human health and the environment. Used engine oils contain PAHs, oil conditioners, antioxidants, trace levels of chlorinated solvents, polychlorinated biphenyls (PCBs) [36
], and heavy metals [31
]. Waste oils have been shown to be mutagenic and teratogenic. Furthermore, fetotoxic and genotoxic effects have also been reported [39
]. Used oils are therefore considered one of the most dangerous types of pollutants.
Another vital aspect of the issue is its economic dimension. A recycled lubricating oil preserves valuable resources and reduces CO2
]. About 67 liters of crude oil are needed to produce 1 liter of lubricating oil but in the case of re-refining, only 1.6 liters of used oil are needed to recover 1 liter of base oil [24
]. This example illustrates the importance of responsible oil management at all stages of its use, collection, and reuse. A rational economy is also supported by appropriate legal regulations regarding the management of used lubricating oil, e.g., the Waste Framework Directive 2008/98/EC [25
]. Another consumer behavior causing economic and environmental problems is the fact that oil users do not often make optimal decisions regarding oil change intervals. Some of them change oil too early, thus generating unnecessary costs for themselves and the environment, mainly due to only partial use of the oil’s potential. Some of them change the oil too late, degrading the technical condition of the engine, exposing themselves and the environment to the negative consequences of unnecessary vehicle repairs, and making the oil more harmful to the environment, thus hindering its recycling.
As mentioned above, more and more consumers are realizing the wider consequences of their purchasing decisions. Consumers are beginning to understand that by acting rationally with used oils, they can have a positive impact on the state of the environment. In the decision-making process, a responsible consumer tries to take into account the economic, social and environmental aspects, and to conform to the principles of sustainable development throughout the entire consumer chain [41
], such as the type and number of products purchased, their use and disposal. In addition, as suggested by [13
], buying environmentally friendly products is one of several activities by which consumers can embody their ideals regarding the active protection of the environment. They now recognize that not only the manufacturer but also the consumer should be responsible for the environmental aspects of the use of engine oils. Oil producers need to continue to increase their efforts to better inform consumers which oils are environmentally friendly or at least neutral to the environment.
In the literature, there is a large body of research on consumer environmental behavior in relation to everyday products such as food [43
], cleaning supplies [46
] or products that have a labeling policy regulated by law, e.g., household appliances [47
]. However, there are no such studies for engine oils intended for use in passenger cars. In their previous study [48
], the authors of this article examined selected aspects of the consumer decision-making process regarding the choice of new engine oil. The research focused on regular drivers, i.e., people who use cars to meet their mobility and transportation needs. Professional drivers comprise a much smaller group in society; however, compared to regular drivers, they generally use their vehicles more intensively. Taxi drivers constitute an important segment of professional drivers. Passenger transport is the main task of the taxi drivers. In order to provide an economic and safe service, they have to maintain the proper technical condition of the vehicle [49
]. They care about avoiding car breakdowns to maintain earnings continuity. Therefore, they need the necessary skills to recognize early symptoms of vehicle failure [50
]. Taxi drivers also often exchange experiences regarding the use of vehicles with other professional drivers and thus improve the quality of their car’s maintenance [51
]. These technical characteristics mostly distinguish taxi drivers from regular drivers who are less likely to devote as much time and attention to proper car maintenance, with careful engine oil selection not being an exception.
The aim of this paper is to present the research results on the decision-making processes of professional drivers when they choose a new engine oil. Unlike in the previous study [48
], the analysis was extended to include the environmental aspects, and especially in this context, the article fills the gap in the literature as indicated above.
The literature does not provide conclusive evidence as to whether consumers are willing to pay more for environmentally friendly products. The results presented by Biswas and Roy suggest that the price, availability, and quality of products have an impact on consumer decisions regarding the purchase of eco-friendly products [62
]. Similar conclusions can be drawn from the research presented in [63
], where it is shown that consumers accepting a higher price of environmentally friendly products want to reward companies engaged in environmental protection. In turn, Ali and Ahmad [65
] provided partly different conclusions, indicating that consumers were more willing to buy eco-friendly goods if such products were competitive in terms of price and quality compared to traditional ones. However, among consumers who were concerned about the state of the environment, there was more acceptance of a higher price for eco-friendly products. According to the study by Pars et al. [66
], 73% of customers were willing to accept a price increase for a meal served in a restaurant that engages in responsible environmental practices. However, only half of the customers were willing to accept a price increase of at most 5%. With a larger price increase (up to 10%), only 15% of customers retained that opinion.
Similarly, to the above, it can be stated that not all professional drivers are ready to incur additional costs related to the purchase of environmentally friendly engine oils. Of the drivers surveyed, only 26% declared a definite interest in engine oils marked as eco-friendly. Conditional interest (if the price was lower) was indicated by 28% of the respondents. Taxi drivers for whom a low oil price is very important or important in the purchasing process, to a large extent (58% and 50%) declared interest in environmentally friendly oils, assuming that their price would be lower. A definite preference for oils marked as environmentally friendly was declared by about 40% of the drivers for whom the price in the purchasing process is of little or no importance. Other respondents (46%) declared no interest in such oils. Among them, 15% of the respondents stated that they did not trust eco-friendly products. Based on the results, a typical supporter of environmentally friendly engine oils is a driver of 40–50 years of age, driving a rather new car (under 10 years old) with low mileage (below 100k km), whereas a typical skeptic toward eco-labeled oils is a younger driver (under 30 years of age), driving an older car (above 10 years old) with rather high mileage (above 300k km). It is also worth mentioning one additional element environmentally differentiating the group of professional drivers from regular ones – 30% of the respondents (this is noticeably more than among regular drivers – 20%) declared an oil change in their own garage or in the garage of their acquaintance. From an environmental point of view, the replacement of used engine oils in private garages is not environmentally welcome practice because it does not ensure proper and controlled collection and management. This clearly shows that more needs to be done to lower both percentages.
It is also important to provide the consumer with information that would make it possible to distinguish eco-friendly products from non-eco-friendly ones or products of unknown ecological status [13
]. The most common is the use of eco-labels that can help consumers make decisions about pro-environmental products [67
]. In the context of engine oils, such a label may not be sufficient, because in the group of regular drivers as well as in the group of professional drivers, over 50% of the respondents (52% and 51%, respectively) indicated that the information placed on the label was of no importance in their purchasing process. Therefore, it is necessary to conduct further research aimed at finding effective information channels on the pro-environmental aspects of engine oils.
Using a model-based clustering it was revealed that taxi drivers do not constitute a single homogenous group. They cluster into two groups with differing importance profiles as the BIC strongly favored a mixture model with two segments. Nevertheless, one of the segments clearly dominates because it comprises 81% of the respondents. These are drivers who primarily pay attention to technical oil parameters (viscosity, quality, OEM specifications) and rely on the recommendations of car manufacturers and employees of local garages. The importance of oil being environmentally friendly is a factor differentiating the subgroups. A definite interest in engine oils with the same technical parameters but additionally marked as environmentally friendly was indicated by 29% of the respondents from the first segment. In segment 2, this percentage was much lower and amounted to 15%.
Results also suggest that the importance of the analyzed criteria affecting the choice of a particular oil brand varies between regular and professional drivers. The most important purchase criterion for drivers of both groups is the qualitative classification and viscosity classification; however, professional drivers indicate higher importance of brand loyalty, recommendations of oil sellers and recommendations of local garage and car service stations.
The analysis of consumer decision-making suggests that there is a need to put additional efforts to provide easily accessible and clearly visible technical specifications on the product label. The professional drivers comprising the largest segment were mainly guided by these specific data in the purchasing process. This was also true for drivers in the second segment but to a lesser degree. In both segments, unconditional preference for environmentally friendly engine oils was rather low suggesting that additional efforts to promote this kind of products may be necessary.
The analysis presented in this article has its limitations, which mainly result from the selection of one particular group of professional taxi drivers. It allowed for more focused conclusions but at the same time, it limited generalizability.
An interesting direction for future research may be the inclusion in the questionnaire questions about the harmful effects of engine oils on the environment and the analysis of the perception of these threats by the respondents representing both regular and professional drivers.