That's just one example. Lots of things can cause delays. And your 10 minute plan gets complicated when you consider they pick up passengers at multiple stops

That's just one example. Lots of things can cause delays. And your 10 minute plan gets complicated when you consider they pick up passengers at multiple stops along the way. If they waited an extra 10 minutes at every stop they might ending up causing themselves an even bigger delay. But I don't have specific info on what things are causing the most delays.