|highway = trunk_link|
|The link roads (sliproads / ramps) leading to and from a trunk highway|
|Rendering in openstreetmap-carto|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
Also used for "channelised" (physically separated by an obstruction or painted island) at-grade turning lanes connecting the through carriageways/through lanes of a highway=trunk to other minor roadways.
Slip roads/ramps are usually considered to "belong" to the through highway they exit and enter. This is usually the higher classification of the intersecting highways because on and off ramps almost always have the same kind of restrictions as the main road. Therefore, highway=trunk_link should be used on a slip road/ramp which connects a highway=trunk to a primary, secondary, or minor highway.
See Link_(highway) for details and exceptions
How to map
To map a simple primary link highway you can just draw a line for it. Select the way and tag with highway=trunk_link. Use oneway=yes when it is not possible to drive in both directions on the highway. Make sure the way points in the same direction as the one way goes, otherwise reverse the direction or use oneway=-1.
To attach more information for the highway you should add further keys:
- destination=* - Link roads normally do not have names. Please use destination=* and its extensions tag to give the cross-street's ref=* and signed destinations such as a city or the name of the destination street, so that routing engines can correctly announce the exit to the "name or ref of the destination street" as you enter the _link
- maxspeed=number The maximum speed, in kilometers per hour which is allowed on the road, for example 120
- maxweight=number The weight limit in tonnes, for example 5.5
- lanes=* The number of lanes