片道 and 往復: one way and round trip
Distinguish one-way from round-trip distance, time, and fares.
One direction only
片道 (かたみち) is the journey in one direction from departure point to destination. 「片道一時間かかります」 says that the one-way journey takes one hour.
「片道の切符を買いました」 means buying a one-way ticket. It does not establish that there is no plan to return; a return ticket may be bought separately.
The outward and return journeys
往復 (おうふく) covers going and returning. 「往復で二時間かかりました」 means that the outward and return journeys took two hours in total.
「駅と家を往復しました」 means traveling back and forth between the station and home. Context may involve repeated trips, so 往復 is not limited to ticket types.
The scope of a number
「片道五百円、往復千円です」 gives a particular fare: 500 yen one way and 1,000 yen round trip. It is double here, but do not generalize that to every route.
「往復の時間には待ち時間を含みません」 excludes waiting from the round-trip time. Check both the journey scope and included activities to determine the total time.
Does 「往復三十分」 mean thirty minutes in each direction?
Show the answer and why
No. It means thirty minutes for the combined journeys, without establishing equal time in each direction.