Proposing an new speed_limit_implied=yes tag for roads with default speed limits where for some reason mapper was unable to be more specific

[Jofban]

Honestly, I feel like a MapRoulette challenge or similar would be a cleaner solution. The information “The mapper didn’t find anything here”, I’d argue, isn’t that useful apart from mapping itself. There are few instances where we tag the non-existence of things - hence MapRoulette.

@rhhs

The information could be combined with information collected by other mappers such as way sections where the speed limit zone is known, location of speed limit and city limit signs, etc. to logically conclude by an armchair mapper (or even a router) what the speed limit of that “no speed limit sign” way must be.

The point of tagging speed limits on ways is exactly to avoid that and have the information locally. And if a router does something like this, the difference between “There is no sign here” and “We don’t know if there is a sign here” is quite small.

In summary, while this info could be useful in some instances, I don’t think it belongs in OSM. Having that tag shows the coverage OSM really has and may provide increased confidence in its correctness - though I’d rather see it as an add-on rather than in OSM itself.