While I am aware of Microdecisions, inc. v. Skinner makes anything made by the state of Florida public domain I am not sure if that makes this public domain due to the fact that if you look at the footer it’s a project in conjunction with MDX (Miami Dade Expressway Authority) which is am not certain that the court ruling applies to so while FDOT cannot claim copyright over that website MDX might. That’s why even though I’ve been watching that website for over a year and a half now I haven’t used it as a source. There is also the fact that allot of the videos are really on YouTube which further complicates things, I am not certain that law applies to YouTube videos made by Fl. 

As for the (now 2) “abandoned” way, it is not, it is either going to be incorporated into some other part of the highway or a highway ramp or be razed and covered in grass. I have seen many highway construction projects here in Miami dade county (I’ve been living here since 2005) over the years and not once have they left a temporary highway_link there once construction finished, they always end up demolished if they haven’t been incorporated into the wider highway structure. That’s why it should be 
left as construction or removed altogether. If you want to map these for historical reasons map them on OHM. As a note, from my understanding when something is under construction it is by definition closed, so mapping the way as under construction would achieve that perfectly. 

Happy mapping 
Udar