lane section per direction
For each change of the number of lanes one has to create a new lane section although there is only alteration in one direction. While modeling real world scenarios with additional lanes for parking, gutter, curbstone, grass verge, pedestrians and bikeway there is the need of dealing a lot with increasing/decreasing the number of the lanes. And additionally then we have to keep in mind the other direction... That results in many lane section that are partly very short.
It would be helpful if a lane section is only valid for one direction. That could be realized by dividing the road element in a right hand and left hand part and apply everything else underneath a right/left element.