Korea Motorways
Motorways in Korea are tagged as highway=motorway, and indicated in real life with a blue and red shield with a number. In general motorways are all toll roads. Tollgates are located at every on- and off-ramp.
Some National Roads(highway=primary) and local roads(highway=secondary) have upgraded sections with Motorway-class restrictions. To indicate this, simply add motorroad=yes.
How to map
Follow the general instructions in the OSM wiki. Add name=* if known (See Korea Motorway Names for a list). For tunnels and bridges the name=* will be different for the bridge or tunnel section, but please ensure that ref=* stays the same.
In the example image the tags are:
highway=motorway oneway=yes (Motorways are drawn as two ways, one in each direction) ref=10 name=남해고속도로 name:en=Namhae Expressway name:ko=남해고속도로 name:ko-Latn=Namhaegosokdoro
Interchanges and Junctions
There are two kinds of interchange. The first is where there is an entrance to or exit from the motorway. These are signed with the name of the interchange followed by 'IC' or a motorway exit symbol: 
.
The second kind is where two motorways meet or cross and it is possible to change from one to the other. These are signed with the name of the junction followed by 'JC' or 분기점.
How to map
Interchanges (IC)
Follow the main wiki instructions to tag the exit node. Add name=* and ref=* to record the IC name and exit number.
highway=motorway_junction ref=23 name=진주IC name:en=Jinju IC name:ko=진주IC
The link roads leading to or from the motorway should be tagged highway=motorway_link and oneway=yes. There are no tags needed for the node where the link road joins the motorway itself. Link roads have no name=* or ref=* tags.
The link roads will pass through a toll plaza. One node on each road should be tagged barrier=toll_booth, with the name of the tollbooth added (this is usually the same as the name of the exit).
barrier=toll_booth name=진주 name:en=Jinju name:ko=진주
Junctions (JC)
Follow the main wiki instructions to tag the junction node where the link road leaves the first motorway. Add name=* and ref=* to record the JC name and number. Replace '분기점' with 'JC'.
highway=motorway_junction ref=27A name=고령JC name:en=Goryeong JC name:ko=고령JC
The link roads between the motorways should be tagged highway=motorway_link and oneway=yes. There are no tags needed for the node where the link road joins the second motorway. Link roads have no name=* or ref=* tags.