D0 motorway (Czech Republic)

D0 motorway (), formerly R1 expressway (), also Prague Ring () is a motorway in the Czech Republic. It is an outer ring of Prague. Its first segment was opened in the 1980s.
 40 km, from the planned length 80 km, are in operation. Two disjunct sections are opened to the public, one going all the way from the Ruzyně Airport to the interchange with the D1 highway, the other one being a road on the eastern border of Prague. A section connecting these two segments is to be built next. Other segments under preparation include a controversial bridge over the Vltava river near Suchdol, with locals proposing the road to be built in a less inhabited location to the north.