Develop a web-based transportation management application utilizing PHP programming language that empowers its users to maintain their various transportation schedules efficiently. The app should consist of a user-friendly interface that allows users to add, modify, and remove their transportation schedules seamlessly. The application should be responsive and accessible across multiple devices, and it should incorporate secure authentication and authorization mechanisms in line with industry standards. Additionally, the application should have features that enable users to set reminders for transportation schedules, track transportation routes, and view past transportation activities.
This prompt doesn't seem malicious.