This paper presents Transit, a comprehensive web-based Transit Management System (TMS) designed to automate, centralize, and optimize fleet operations. Built on a CodeIgniter (PHP) MVC backend, MySQL relational database, and Bootstrap 4 responsive frontend, Transit integrates GPS-based real-time vehicle tracking, automated booking workflows, route management, fuel consumption logging, proactive maintenance reminders, income and expense tracking, and a role-based multi-user administration interface. The system supports geofencing with automated boundary alerts and provides rich, exportable reports for managerial decision-making. Thorough unit, integration, system, regression, usability, and security testing was conducted, with all 18 defined test cases achieving a Pass status. Evaluation results indicate measurable improvements: an estimated 30% reduction in operational costs, 25% improvement in fleet utilization, and 50% acceleration in report generation. The paper discusses the system architecture, module design, technology stack, testing results, and future enhancement pathways, positioning Transit as a scalable and practical solution for both small enterprises and large-scale logistics corporations.