4 digit road and trunk classification guide in WikiProject Thailand


The guideline for secondary road states that “Note that new roads often receive a 4-digit reference number, regardless of their importance - they might also be primaries or tertiaries.” which is quite confusing, so how do we know if a 4 digit road is primary, secondary or tertiary?

Also, in highway=trunk it says “If sections of other highways fulfil the above specification, those sections should also be classified as trunk roads.” which seems to rely on physical characteristics, which I believe should not be the case. Could anyone elaborate on this?

I think the argument was generally that since the number of digits in a road’s ref number correlated poorly with its importance, it should not be exclusively used to determine a road’s classification. While a road’s physical characteristics (e.g. surface, number of lanes) should be tagged as such, they can also help to give a rough idea of what the road’s importance is. You can see how we arrived here in this thread.

The sentences you quote could be better phrased though. If someone wants to improve the wording please do so. In the end, I think the duck test applies: If it looks like a primary highway and carries traffic like a primary highway, tag it as highway=primary."