往復 and 往来: travel out and back versus traffic on a street
Compare daily journeys between home and a station with morning traffic on a street, distinguishing the return relationship from the pattern of passage.
Going between home and the station each day
往復 (おうふく) describes going out and returning. 「家と駅の間を毎日歩いて往復しています。」 says that the speaker walks back and forth between home and the station every day.
家と駅の間 identifies the section between home and the station, and 毎日 marks repetition. The sentence describes recurring daily travel rather than one completed trip.
Morning traffic on a street
往来 (おうらい) focuses on movement to and fro. 「朝になると、この通りは人の往来が激しくなる。」 says that the street becomes busy with people passing along it in the morning.
The focus is the pattern of passage along the street. The sentence does not supply each person's starting point or place of return.
A return relationship and a pattern of passage
The 往復 example connects travel out and back with the two points, home and the station. The 往来 example describes the street's increase in traffic in the morning.
Do not limit 往復 to a single trip or 往来 exclusively to movement by several people. This comparison concerns travel relationships and traffic patterns, without adding time or fare calculations.
Does 「家と駅の間を毎日歩いて往復しています。」 describe only one round trip?
Show the answer and why
No. 毎日 and 往復しています describe walking out and back between home and the station every day.