Totally agree uncertainty is a problem - both when taking public transport and when using computer software - but in both cases it's surely better to primarily focus on ensuring operations aren't delayed unnecessarily, and only once you've got to a point that further optimisations become too difficult or expensive, turn to providing more accurate feedback on expected waiting times. I will say though accurately estimating waiting times (and esp. providing continual feedback on them) isn't always significantly less challenging than reducing them in the first place.