I’m skeptical. There was a big thing about a 100 mile bike trail going through my county but when I looked it up, 3/4 of it was just dumping you on various roads and they counted that as part of the trail.
Bicycle route mapping is an iterative process, and often relies upon local cyclists recommending the best routes that they know of through a given area.
Cycling communities often provide guidance and cautions about route sections, and if you become familiar with cities & counties then you may be able to let them know about risk areas and possible improvements.
That said, if you want to cycle a given route and you know of better options than the existing roads, let the trail mappers know; it could lead to learning a bit more about their choices, and perhaps improvements to the maps.
Beyond that, let's hope that more roads and infrastructure are constructed with cycling in mind so that trail routes can be improved. It's an inexpensive, healthy transit method that fits to your own schedule.
