Road construction procedures

A single-track road or one-lane road is a road that permits two-way travel but is not wide enough in most places to allow vehicles to pass one another.
This kind of road is common in rural areas across the United Kingdom and elsewhere.
To accommodate two-way traffic, many single-track roads, especially those officially designated as such, are provided with passing places or pullouts or turnouts, or simply wide spots in the road, which may be scarcely longer than a typical car using the road.
The distance between passing places varies considerably, depending on the terrain and the volume of traffic on the road.
The railway equivalent for passing places are passing loops.

The Underwater Road Tunnel Salamina island - Perama is a planned sub-sea road tunnel in the Attica region of Greece, which will provide a direct road link between the island of Salamis of Islands Regional unit in the Saronic Gulf and the port city of Perama in Piraeus Regional Unit, on the east coast of the Saronic Gulf.
In whole, the project includes the construction of an underwater road tunnel about 1 km long, the construction of a new road section from Schistos Avenue to the tunnel's entrance in Perama, as well as two new interchanges connecting the adjacent road network in Salamis and Perama.