smooth (without difficulty)

(attributive) the state of being shaped like a circle or ring; annularity, orbicularity, circularity, cyclicality, cricoidness, etc.

flow / transpiring; events

to travel along a specific route / to have contact with other people, to engage in social intercourse

transportation / traffic

road, street, a way for local traffic

a traffic accident

transportation facilities

a roadblock

residential road