A significant number of people prefer road transport instead of the rail one. Providently, the number of express bus routes is increasing over the years, while some of their service time is limited to the rush hours. Estimated time of arrival (ETA) can definitely help one's traffic planning in different user cases, e.g., waiting 10 more minutes for the express route or taking a just-in-time long journey bus.
HK Bus companies have already launched their ETA apps for a few years. However, these companies sacrifice the user experience for their own earnings by numerous ads, even a full-screen blocking one. The project is to launch an fast and ad-free ETA application to cover the three (or more) major bus routes in Hong Kong.
App link: https://chunlaw.github.io/hk-independent-bus-eta/