In the transportation planning, transport policy-makers must simultaneously consider the trade-off between differences in the supply of transport infrastructure or modes, in addition to the various needs of stakeholders. Transportation needs are derived from daily life and comprise diverse urban activities. Failure to satisfy basic stakeholder needs can negatively impact quality of life. Quality of life is defined by the World Health Organization Quality of Life (WHOQOL) Group (1998) as the perceptions of individuals regarding their goals, expectations, standards, and concerns. Furthermore, Diener et al. (1999) defined quality of life as a multi-dimensional construct, comprising the level of satisfaction of important individual needs. As a result, the simultaneous consideration of richness and evenness creates issues related to transport diversity.
Although the common identified definition of sustainability is not available, van Kamp et al. (2003) examined the overlap between the concept so quality of life and sustainability, as a result of which the two concepts are frequently used as synonyms. In fact, Yang (2002) argued that the need for quality of life involves not only individual health, safety, social justice, income, and freedom, but also relationships with salient features of the environment, such as fresh air, clean water, and natural surroundings. Besides, Shafer et al. (2000) identified sustainability as the ability to develop good quality of life in both the present and the future. In addition to indicators, the Commission of the European Communities (2002)
introduced the Sustainability Impact Assessment (SIA) process for developing an integrated assessment system based on existing fragmented sectoral systems, for identifying impacts of policies, and for determining the trade-off among competing objectives. McMahon (2002) examined whether the needs should combine both top-down and bottom-up approaches to measure quality of life and to monitor sustainability.
The concept and content of quality of life and sustainability are similar. However, satisfaction of needs differentiate quality of life from sustainability in this study. Quality of life represents the basic level of needs satisfied with which stakeholders certainly live without deficiencies. Likewise, Topolski et al. (2004) believed that quality of life, utilized as a descriptor, evaluative report, or normative statement, may assess the living status referring to the limitations of socio-economic activities. In comparison, sustainability indicates the expected target of sustainable development. Sustainable development is generally conceived as finding a balance among environmental, social and economic qualities (George, 2001;
Kasemir et al., 2003; Steg and Gifford, 2005; Ness et al., 2007). Moreover, the WCED (1987) defined sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their own needs”. Additionally, Pope et al. (2004) suggested that it is necessary to explore not only the direction to sustainable target but also the distance from sustainability.
Transportation behaviors are the most common activities in daily life. Needs for transport infrastructure and services differ among transport stakeholders. Although most transport services are provided by public sections, the service levels of transport system have increased substantially around the world during past decades, particularly in metropolitan areas of developed countries, due to a shift towards a culture of requiring that the performance of government should be as efficient as that of private businesses. This raises concerns regarding maintaining transport quality in the face of changing social and lifestyle patterns that are generating increasingly diverse travel needs. In fact, policy-makers cannot simply create services, provide them, and hope for the best. To decide how to improve service quality of transport system, policy-makers must first understand how stakeholders view their services via valid measuring instruments to effectively measure user reactions to those services (Carr, 2007).
Numerous studies have discussed service quality in transport industries. Nathanail (2008) addressed service quality for railway passengers. Qualitative studies of bus users were presented to improve understanding of traveler attitudes regarding public transport and explore perceptions of bus service quality (Hensher et al., 2003; Wall and McDonald, 2007).
Moreover, lots of literatures assessed service quality for airline and air cargo services through various constructs and measures to analyze the relationships among performance, competition, critical factors, and customer satisfaction (Rhoades and Waguespack Jr, 2000; Tsaur et al.,
2002; Gilbert and Wong, 2003; Gursoy et al., 2005; Chen and Chang, 2005; Liou and Tzeng, 2007; Wang, 2007; Pakdil and Aydm, 2007; Park, 2007). Additionally, Beirao and Cabral (2007) conducted in-depth interviews to obtain the main influences on modal choice of travelers and attitudes towards public transport and private cars. However, few studies have discussed total quality management as a method of improving urban transport system service quality to satisfy stakeholder needs.
Service quality is more difficult to describe and assess than product quality owing to the intangibility, heterogeneity, inseparability, and perishability of the service industry. Gronroos (1984) argued that customer perceptions of service quality comprise technical quality, namely the assessment of the core services that the buyer receives from the seller, and functional quality, namely the evaluation of the service delivery process reflecting customer experiences of service quality. Parasuraman et al. (1985) proposed a gap framework that identifies overall service quality using five gaps, where the first gap occurs when customer expectations regarding service differ from managerial perceptions of those expectations. Meanwhile, the fifth gap, service quality, refers to the degree and direction of difference between customer perceptions and expectations. For service providers, precisely identifying customer expectations is the most critical step in defining service quality (Zeithaml et al., 1990).
Besides, Parasuraman et al. (1988) suggested the SERVQUAL scale based on factor analytic psychometric research in which service quality was assessed using five constructs, including tangibles, responsiveness, assurance, empathy, and reliability.
SERVQUAL has clearly contributed substantially to understanding service quality as well as highlighting the importance of stakeholder reactions to services (Carr, 2007). The original SERVQUAL involves 22 items arranged into five dimensions, and provided a basis for the following labels and concise definitions (Parasuraman et al., 1988). Tangibles:
Physical facilities, equipment, and personnel appearance; Responsiveness: Willingness to assist stakeholders and provide prompt service; Assurance: Service provider knowledge and ability to inspire trust and confidence; Empathy: Provision of individualized care and attention for stakeholders; Reliability: Ability to perform the promised service dependably and accurately. However, the fact that numerous studies utilize SERVQUAL and the conceptual model to measure service quality results in inconsistency in attributes among different industries (Triplett et al., 1994; Jiang et al., 2000; Kettinger and Lee, 2005).
Furthermore, Carman (1990) suggested that the items and dimensions should be redesigned based on the procedures proposed by Parasuraman et al. (1988) according to industry characteristics since SERVQUAL has been developed to provide a basic skeleton for measuring service quality. Additionally, Hinkin (1998) provided a process for developing survey questionnaire scales. The items for assessing service quality of transport system are thus based on the five dimensions and scale development process mentioned previously.