I'm probably just old, but there's more than one case of an Internet map telling folks to turn somewhere that there was no where to go because the maps aren't updated. I also used to used the old fashioned paper maps before MapQuest and while those were usually fine, they also don't help in cases of road closures or construction changes.

Whoever's responsibile for the road itself (local municipality or state) should have had it blocked off.

the fact that Google does not pay attention when users notify them about dangerous road conditions in their maps is a serious problem,

Again, as someone who grew up using paper maps, this is such a bizarre statement. It's cool that map companies offer things like speed trap warnings, but I frequently get warnings about stuff and there's nothing there. You still can't fully trust what the system is telling you. It's just a tool.