[AlotOfReading]

To standardize a journey time in a scheduled system, you subtract the origin scheduled arrival from the destination scheduled arrival. Map apps will even do this for you automatically. If the bus is unreliable, you add error margin. A demand shuttle system usually has a much larger variance, which means you can't predict that the journey time will be acceptable and you'll find some other way to get around.

    How do buses fair in this regard?

You look at the route map and the schedule to decide? Again, map apps make this trivial for regularly scheduled services.