I would probably avoid mapping proposed highways like this one, especially since a full freeway here is likely at least a decade down the road. highway=proposed can be useful for mapping out roads that are to be built in the near future so they can be quickly changed to highway=construction, but one like this where the ROW still needs to be acquired and the actual construction is so far into the future where anything could happen (the routing could be altered, it could be downgraded to an arterial rather than a freeway, or could not happen at all, etc.) is effectively just some more clutter in the editor that makes it a little more difficult to edit around it, especially since these ways cross many other roads and unmapped features like houses. Generally, the less ways the don't render on the map (abandoned, demolished, proposed, etc.), the better.