A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2003

Due to lacking of efficient access modes, travelers living in suburban area of Bangkok inadequately served by public transport services are more likely to use their private vehicles which cause economic and environmental problem as well as the quality of people's life. To avoid these serious problems, some policies of transit incentive should be employed. This study focuses on (1) generating a travel behavioral model for travelers in suburban communities using SEM, (2) studying the characteristics and behaviors of both travelers and access modes, and (3) introducing and analyzing some policies to attract choice riders to shift their modes from private vehicles to transit services and to enhance the quality of traveling for captive riders. The structural equations analysis can be used to reveal and examine the decision making process on mode. The structural equation model can extract personal attitude and perception and handle the measurement errors often associated with travel time and travel cost. The model presented in this study can be extended to the analysis of more complex decision process such as more detailed analysis of modes, activities, and times. All necessary socioeconomic data of respondents including six latent variables of attitude and perceptions toward travel time, travel cost, convenience, comfort, flexibility, and safety were asked by the questionnaire. To improve and propose some new policies, the study of characteristics and behaviors of both travelers and transport services were conducted to gain more understanding. Travelers in the study area need certain services for connecting them to the main network. To decrease their total travel times, such services need to approach the characteristics of private transport rather than those of fixed routes and fixed scheduled services. Accordingly, motorcycle-taxi is very popular in this area and plays the most significant role as a short haul transport mode shuttling people from their houses to the transit stops due to its less time-consuming, mobility, and demand-responsive ability. Moreover, motorcycle-taxi is sometimes used as a long haul mode for beating the traffic during times of congestion. However, motorcycle-taxi is not so popular among some groups of people such as elderly, handicapped, and women due to its unsafe condition. The proposed policy in this study is the introduction of shuttle bus transferring people to the railway station. The pilot project was adopted by the owner of this study area to serve the transport needs of residents. The before-and-after opinion survey was employed in this stage. The results showed that this project was warmly welcomed by the travelers considering it as their new travel mode choice.