Hi,

https://www.openstreetmap.org/node/1948210328 You should only add highway=turning_circle when there is a definite place for vehicles to turn. There is more information here: https://wiki.openstreetmap.org/wiki/Tag:highway=turning_circle

In general, roads, paths, driveways, etc. should connect up. However, you will have places like golf courses and farms where they don't connect.