Off the top of my head, I'm not sure which exact ones would be built soonest, other than some residential streets in multi-phase subdivision projects, or any other major road we know is scheduled to be built (like the Hollywood Blvd extension for example). 

I wouldn't necessarily go out of my way and make a mass-deletion of them since in reality most of them aren't truly problematic more than they are sometimes annoying and inconvenient if they overlap with or are attached to a bunch of other features—but I also wouldn't discourage going about deleting them either. I would just suggest not mass-deleting them in the event there are some that are out there that are useful to keep (like I had mentioned in my above comment), but instead delete ones you find are in the way of what you're doing or any blatantly false ones you stumble across in ID. This strategy would probably be less time consuming and/or prone to breaking something than identifying which exact ones to keep out of the hundreds or so that exist in this area and deleting the identified ones in one changeset. Ultimately, it's probably not worth prioritizing because this object only renders in very select map styles and the data isn't ever used elsewhere (as far as I know).

The simplest solution, though, and the rule of thumb I go by now, would be to just not map proposed roads that aren't 100% confirmed or construction takes place in an unreasonably late date to even think about it in the present, and rather use it as a sort of scaffolding for mapping new road that do get built soon so you can quickly change them with the construction and get the data out there as soon as possible rather than have to take time and start fresh after construction has already started.