|highway||primary|| A major highway linking large towns, normally with 2 lanes. The traffic for both directions is usually not separated
by a central barrier.
|highway||secondary|| A highway which is not part of a major route, but nevertheless forming a link in the national route network.
It normally has 2 lanes. The traffic for both directions is usually separated by a central line on the road.
|highway||tertiary|| Used for roads connecting smaller settlements, and within large settlements for roads connecting local centres.
In terms of the transportation network, OpenStreetMap "tertiary" roads commonly also connect minor streets to more major roads.
|highway||unclassified|| Used for minor public roads typically at the lowest level of the interconnecting grid network. Unclassified
roads have lower importance in the road network than tertiary roads, and are not residential streets or agricultural tracks. Unclassified roads are considered usable by motor cars. Do not use this tag for roads where the OSM highway=* tag value has not been determined yet. Use highway=road for those.
|highway||residential|| This tag is used for roads accessing or around residential areas but which are not a classified or unclassified
highway. Street or road generally used only by people that live on that road or roads that branch off it.
|highway||track|| This tag represents roads for mostly agricultural use, forest tracks etc.; usually unpaved (unsealed) but may
occasionally apply to paved tracks as well, that are suitable for two-track vehicles, such as tractors or jeeps. If the way is not wide enough for a two-track vehicle, it should be tagged as highway=path.
|highway||path|| A route open to the public which is not intended for motor vehicles, unless so tagged separately. This includes
snowmobile trails, ski trails, hiking trails, horse trails, bike trails and paths, mountain bike trails as well as combinations of the above and other modes of transportation. These routes may have any type of surface.
|highway||road|| Road with an unknown classification. This tag should be used temporarily until the road has been properly
surveyed. Once it is surveyed the highway tag should be changed to record the appropriate classification. When this tag is used it implies a FIXME. So you do not need to add a todo=FIXME, fixme="Unknown classification", etc. It's just duplicate work for the next person to change the highway type AND remove the fixme tag.