## 2 Literature Review  
### Bus Service Quality  
In the context of education, according to researchers, service quality is defined as the gap between a customer's initial expectations and their actual experience with a particular service provider, [16]. For the evaluation of service quality, the SERQUAL model is one of the most commonly used models [17]. The widely used SERQUAL model, developed by [PERSON] et al. [18], is an effective tool for evaluating service quality that analyzes the gap between customer expectations and perceptions of an organization's service quality performance. Service quality is determined by two factors: perceived quality and expected quality. Perceived quality is the customer's evaluation of the overall status and excellence of the service provided, while expected quality refers to the customer's anticipated level of service [19]. The SERQUAL scale, also known as gap analysis, measures the extent to which the service quality meets customer expectations [20]. According to [PERSON] et al. [18], service quality can be defined as the sum of positive and negative service features that occur during the interaction process between the service provider and the customer. To assess service quality, [PERSON] et al. [18] proposed a SERVQUAL scale that includes five crucial aspects of quality (tangibility, reliability, responsiveness, assurance, and empathy) to assess service quality. These five aspects serve as the evaluation criteria and provide a practical measure for assessing service quality. The satisfaction and perception of the quality of the public transport system are crucial to its success. [PERSON] et al. [21] demonstrated that improving the cleanliness and ventilation of vehicles can have a dual effect on increasing user satisfaction and improving the overall impression of public transport quality. This in turn may attract more private car users to switch to public transportation. Therefore, an improvement in these elements should be a starting point in the process of enhancing the quality of public transport services with a focus on meeting the needs of both users and non-users. [PERSON] and [PERSON] [22] conducted a study to examine the impact of perceived service quality on the perception of both current and potential users of bus services in Belfast City, UK. Their research revealed 11 key factors that influence passengers' perceptions of the service. These factors include the frequency and reliability of the service, waiting and transfer times, security at stops/stations, bus comfort, availability of discounted tickets, information at stops/stations, bus fares, needs for transfers, bus stop locations, and availability of park and ride services. [PERSON] and [PERSON] [23] conducted a study on the bus service of the Bangkok Mass Transit Authority (BMTA) and identified areas where improvements were needed. The most pressing issue was the timeliness of the buses followed by the frequency or continuity of the buses, the poor condition of the buses, the coverage/thoroughness of the bus routes, the safety of the service, and the quality of the buses. By improving and developing the quality of the bus services, the majority of users were likely to switch to using more BMTA bus services. In a separate study, [PERSON] [6] investigated the factors that influence Bangkok commuters to switch from driving cars to using buses. The results showed that the top three factors were bus punctuality, sense of safety, and routing information, while payment methods and bus fare were the least important factors. The researcher recommended several improvements to the Bangkok Mass Transit Authority (BMTA) based on the study results. These included increasing the number of buses to reduce waiting times, providing clear and accurate information about bus routes and arrival times at each bus stop, and enhancing the mobile application to estimate the correct arrival time of the bus for which commuters are waiting.