This research delves into the factors that influence individuals' choices when selecting transportation applications in the bustling urban environment of Bangkok, Thailand. The study focuses on perceived usefulness, perceived ease of use, perceived efficiency, and system availability as key determinants shaping users' intentions. Employing a quantitative methodology, the primary data collection method involved the distribution of questionnaires to a sample comprising 400 active users of transportation applications in Bangkok. Convenience sampling was utilized to select participants. The study rigorously tested hypotheses and conducted detailed data analysis using analytical software and statistical techniques. The results have convincingly shown that perceived usefulness, perceived ease of use, perceived efficiency, and system availability collectively hold substantial sway over individuals' intentions when it comes to the adoption of transportation apps in this dynamic urban setting. These findings contribute significantly to a deeper understanding of user behavior and preferences within the realm of modern mobility solutions.