-

[deleted_user_8875]

-

[deleted_user_8875]

.

[Josh0]

Without seeing your map, I cannot say for sure. In general, A.I. vehicles disappear because the game figures out that the vehicles have "no where to go" (in other words, the game cannot find a valid path for the vehicles to travel). If any of the road segments attached to the roundabout, or the roundabout prefab(s) itself, have the "No AI vehicles" checkbox in the Properties window then A.I. traffic might disappear. It is also possible that the roundabout prefab has some A.I. paths disabled. Or the road/prefabs are not actually joined at the nodes. Can you show a picture of the roundabout in the map editor?