In OpenStreetMap, the "highway" `highway` (*not* "type") `type`) tag is used to indicate a road's prominence in the country's road system. There are certain internationally agreed values for this tag: *highway=motorway, `highway=motorway, highway=trunk, highway=primary, highway=secondary, highway=tertiary, highway=unclassified*, highway=unclassified`, and *highway=residential*. `highway=residential`. Different countries have their own rules for what type of road gets what value, and often (though not always) these coincide with administrative classifications. In the UK, for example, "primary A roads" with green signs are tagged *highway=trunk*; `highway=trunk`; other A roads with black-and-white signs are tagged *highway=primary*; `highway=primary`; and B roads are tagged *highway=secondary*. `highway=secondary`. You can read a country-by-country list of these rules [on the wiki][1]. New Zealand doesn't appear to have settled on a consistent set of rules yet. It would be good if it did. You can discuss this on [the local mailing list][2], but you should be aiming to agree on a rule whereby "all state highways are classed as *highway=trunk*, `highway=trunk`, and the *ref* `ref` tag just contains the number" or something like that. [1]: http://wiki.openstreetmap.org/wiki/Key:highway#International_equivalence [2]: http://groups.google.com/group/nzopengis

In OpenStreetMap, the "highway" (*not* "type") tag is used to indicate a road's prominence in the country's road system. There are certain internationally agreed values for this tag: *highway=motorway, highway=trunk, highway=primary, highway=secondary, highway=tertiary, highway=unclassified*, and *highway=residential*. Different countries have their own rules for what type of road gets what value, and often (though not always) these coincide with administrative classifications. In the UK, for example, "primary A roads" with green signs are tagged *highway=trunk*; other A roads with black-and-white signs are tagged *highway=primary*; and B roads are tagged *highway=secondary*. You can read a country-by-country list of these rules [on the wiki][1]. New Zealand doesn't appear to have settled on a consistent set of rules yet. It would be good if it did. You can discuss this on [the local mailing list][2], but you should be aiming to agree on a rule whereby "all state highways are classed as *highway=trunk*, and the *ref* tag just contains the number" or something like that. [1]: http://wiki.openstreetmap.org/wiki/Key:highway#International_equivalence [2]: http://groups.google.com/group/nzopengis