This was the question asked at a Town Hall meeting that made the news here in Denver...
When will the G-Line be ready for use?
The answer was we don't know. This response reminds me of the notion conjectured by some in the agile community that deadlines are somehow evil. Or better yet, that we can't ever know when we'll be done.
This, of course, is pure nonsense, just like RTD's response to the citizens of Denver is nonsense. Any credible project management process has some idea of what Done looks like, what it will cost to reach Done, and when Done will arrive. This is the very definition of credible.
Now the confidence in those dates and costs may be low or may be high. There may be acceptable or unacceptable levels of accuracy and precision for those estimates. But to be credible an estimate is needed.
No need to have an estimate if your project is de minimis, meaning too trivial or minor to merit consideration. If you have a project that is not trivial or not minor and does not merit consideration, then estimating is part of the adult management process, just as Tim Lister states...
Risk Management is How Adults Manage Projects
Since risk management is about mitigating the risks that come from the uncertainties that unfavorably impact the probability of project success. Reducible uncertainties and Irreducible uncertainties, estimates are always needed for any credible project management method.