Truck transportation has overwhelmingly dominated freight transportation in Thailand. Over 90% of domestic freight movement measured in ton-kilometers have traditionally been served by trucks. Over almost 10 years prior to 1997, the nation experienced an unprecedented economic boom and the supply of motor carrier services was enormously expanded to cater the ever-increasing needs for the services. Unfortunately, following the economic bust occurred in 1997, the demand for trucking services abruptly and substantially shrunk while the carriers were unable to size down their service capacity fast enough to match the reduced demand. Given the heavily excessive supply of trucking services, the competition among motor carriers has become very fierce and motor carriers have been struggling to find ways to enhance their competitive positions. To deal with current intense competitive pressures, carriers must be able to customize services to suit customer requirements at competitive rates. Thorough appreciation of shippers' logistics needs and about the critical criteria used by shippers in selecting motor carriers is therefore crucial to carriers' long-term business success. Although the investigation of criteria used by shippers in purchasing trucking services has attracted great attention of researchers elsewhere, there has been no in-depth study ever attempting to explore the carrier selection criteria in Thailand. There is certainly a serious need for systematic studies that shed light into service attributes crucially relevant to the selection of motor carriers in Thailand. The findings of these studies would be highly beneficial to both motor carriers and shippers. The knowledge about the shippers' service priorities would definitely be useful for carriers in designing their service offerings. As shippers have at their choice the type of motor carrier services that truly suits their logistics needs, they should be able to significantly reduce their logistics cost and improve customer satisfaction.
Our study represents an exercise to fill the gap between prevalent industry needs and the available research works. The
purpose of this study is to determine the relative importance of key service attributes as perceived by shippers in selecting
trucking services. In designing the study, we separate shippers into two groups that likely exhibit different requirements with respect to distribution services. The first group represents the producers of consumer goods who distribute their products to trading firms who in turn offer the goods to satisfy the Journal of the Eastern Asia Society for Transportation Studies, Vol.5, October, 2003 2225 consumption needs of consumers. The second group represents the suppliers of industrial goods who provide materials or parts to serve production activities in downstream manufacturers. Given the limited time and budget made available to our study, industrial goods to be covered in the study include only the automotive parts.
2. RESEARCH METHODOLOGY
The review of past studies into carrier selection decision indicates that the choice of motor carriers can be determined by a relatively large number of service factors and few alternative study approaches have been adopted in the investigation of shippers' attitudes. The approach that has enjoyed the greatest application is the direct questioning method that asks sampled shippers in a direct manner to weigh the importance of service features on a rating scale, with larger numbers indicating greater importance.Another approach widely adopted would perhaps be the "Conjoint Analysis". The conjoint analysis is a broad class of methods that measure respondents' preferences in hypothetical contexts consisting of service alternatives typically defined by combinations of levels of service variables.In typical conjoint experiments, respondents are indirectly urged to make trade-off judgments between attributes because one service bundle may be set as being superior to other bundles in a particular attribute but inferior in other attributes. The preference data enable the firm to derive numeric utility functions and the contribution of each attribute to the utility function. The relative utilities of individual attributes are further analyzed to determine corresponding relative importance. The two approaches have relative strengths and weaknesses. The direct questioning method has strengths in its simplicity and its ability to accommodate a large number of attributes. It, however, suffers from a weakness in that respondents may
mistakenly assume that each service feature can be offered at no charge and there is a strong tendency for respondents to state that all service attributes are important. The conjoint analysis has the advantage of providing not only information about the relative importance of attributes but also other pieces of information directly useful for designing service offerings such as the pricing of non-economic service at tributes. The key drawback of the conjoint analysis is that it usually can deal with only a limited number of attributes.Our study involved three stages of surveys with the application of both the direct questioning and the conjoint analysis. The first stage survey attempted to identify an initial list of potential service elements deemed important by shippers. Given the list of service elements derived from the first stage, the second stage asked respondents to weigh the importance and indicate their satisfaction associated with each service element. The last stage applied the conjoint analysis to ask respondents to choose one of two hypothetical carriers with different combinations of service attribute levels.The following sections will explain the data collection, the analysis, a
nd the results associated with each survey stage