A screed device in a road-paving vehicle such as an asphalt finisher, enabling the width of pavement to be steplessly changed up to about three times the width of the main screed through a simple operation. The product includes a substantially non-porous coating covering its outer surface. The process includes optimizing the identified congestion areas, incrementally rerouting affected nets, testing the resultant design legality and congestion metrics, and committing or reversing the optimizations and reroutings. Accordingly, edges of the facing ends do not sharply act on the contact projection.