Road 1 + 2 means that there is one field for driving on one side and two fields on the other side, and this is to facilitate traffic

The route will look like this:

There are also highways 1 + 2, and there is a driving lane that extends a certain distance to facilitate traffic

In addition, there are signs indicating that there will be two driving fields, an example of which is the following:

The white box containing the arrows shows how far the two fields will be merged to form one field

The point of merging the two fields, and also a sign indicating that there will be one field directly in front of you

If you are approaching the end of the field and want to return to the right field, look at the dead corner to see if there is a car on your right
 If there is a car on your right and you do not have room to return to the right lane
 Then slow down and let the car on the right pass before you. Pay close attention to the traffic coming behind you and avoid braking hard.

On highways, you must also pay attention to branching roads and intersections
 Because highways differ from highways and have interchanges and connected sub-roads.