tbf the unannounced bus detours are usually not Septa's fault but more poor communication from the contractors working on the roads. The amount of times I've seen a bus pull up at an intersection of a closed road and have to let everyone off to walk to a different stop, when the driver clearly didn't even know about the construction, is pretty ridiculous. On the other hand Septa knows about their planned rail work so the app will pop up notifications about those and their impacts well in advance.