I have developed a web application (just for fun) that displays the current positions of buses and trains for the city of Austin Texas, Houston Texas, San Antonio Texas, and New York City MTA Buses.
Please visit transitdata.live to view current positions of the buses.
Most transit agencies around the world allows developer to access the position of the bus/trains. Developing is not easy, but little-by-little, I have been adding (and will be adding) features. Also, I am planning to expand more cities.
While developing, I am surprised how many buses are on the streets, especially New York City. New York City Buses (operated by NYC MTA) operates around between 1000 – 4000 buses a day! That is huge!

While Houston METRO buses operates around almost 800 buses during the weekdays and 200-400 buses during weekends (pretty small).

In the app, you can also view a specific route that you want to see. For example, on Friday night (8:32 p.m. USCT), Houston METRO Route 82 (one of the busiest bus routes in Houston) operates about 24 buses.

