Widening the busy A4 road in Switzerland to four lanes was achieved quickly by using the latest paving technology. Increased traffic required the widening of the A4 from two to four lanes along a 20km section, with two lanes separated by a central divider in each direction. Carrying 20,000-25,000 vehicles/day, the trunk road between Winterthur and Schaffhausen was one of Switzerland's busiest two-lane stretches, and as a result, the Federal Council of Switzerland in Bern planned an enlargement of the dual-l
