Split lane lengthwise into two lanes
The Lane Split Tool is used to split a lane lengthwise into two lanes. Splitting a lane automatically adds a default lane marking that can be changed or removed with the Lane Marking Tool.
On the RoadRunner toolbar, click the Lane Split Tool button:
Click the Lane Split Tool button.
Click the road you want to edit.
Move the pointer to the location you want to split. A light blue line indicates where the split operation will take place.
By default, the lane split affects only the lane between the two nearest intersections. To force the lane split to occur along the entire road, hold the Ctrl key.
Right-click to split the lane.