4 ms·

For busses, the B stop on the way out may be in another zone as the B stop on the way back because they're geographically displaced. For busses and trains, depe

by sshine 8y ago

For busses, the B stop on the way out may be in another zone as the B stop on the way back because they're geographically displaced. For busses and trains, depending on your type of ticket (2-8 zones, 8+ zones, commuter card) and whether the zone intersection is on or between stops/stations, you may have to pay for that zone one way but not the other. Those are edge cases. But the most confusing part is the ring topology (here shown with the zone-ring center being the actual city center): https://passagerpulsen.taenk.dk/sites/default/files/styles/full_width/public/zonekort_movia_hjside830x400.jpg https://passagerpulsen.taenk.dk/sites/default/files/styles/f... When buying 2-8 zones you don't pay for individual zones, but rather rings from your origin zone. Going one way, the zone rings look one way. Going back they look different, because the origin zone is different. A practical example of this peculiarity: You go from Hellerup (zone 2) to Friheden (zone 33) via the central station (zone 1). Your ring 0 is zone 2, and zone 1 and 33 are both in ring 1, so you only pay for two zone(-ring)s: https://dinoffentligetransport.dk/media/1413/svanemollen-friheden.jpg https://dinoffentligetransport.dk/media/1413/svanemollen-fri... You go back from Friheden to Hellerup via the central station: Your ring 0 is zone 33, zone 2 is in ring 1, but zone 1 is in ring 2 this time, so you pay for three zone(-ring)s: https://dinoffentligetransport.dk/media/1411/friheden-svanemollen.jpg https://dinoffentligetransport.dk/media/1411/friheden-svanem... Your origin zone on the way out was adjacent to both other zones needed (needing only 1 ring), but your origin zone on the way back was not (needing 2 rings). So they're not just different prices: The graph that spans train stations via zones in the ring topology is not metric. So getting a return ticket is not the inverse of getting the ticket out. And while you have a ticket that's valid for the timespan of your return, it may not be valid for your return path.

deleted 8y ago
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ZeikJT 8y ago
What the... that was painful to read and comprehend. Was this kind of complexity really necessary? Did someone get a promotion for coming up with this?
- sshine 8y ago
  I copied and translated a quite limited subset of the official traveller guidelines. There are several reasons why it ended up like this, and I don't know all of them. But two reasons I can think of: 1) With the introduction of RFID-based commuter cards, the zone system was revised for traditional ticket types as well. It appears convenient that a price can always be determined by knowing the check-in point, the check-out point and the shortest path in the graph. Unfortunately, with the old ticket types, you have to perform the calculation instead. 2) It is the odd shape of zone 2 that causes some tickets to not work on the way back, even though the trip goes in a straight line. But for a large part of all trips, you only need zone 1 and 2, or zone 2 and zone (30, 31, 32, 33). Only the ones that start in zone 2, go through zone 1, go back into zone 2 and farther into another zone (or vice versa) have the anomaly. (Trips that actually bend can have this too, but it is slightly more intuitive.)

by sshine 8y ago

deleted 8y ago

[deleted]

ZeikJT 8y ago

What the... that was painful to read and comprehend. Was this kind of complexity really necessary? Did someone get a promotion for coming up with this?

sshine 8y ago
I copied and translated a quite limited subset of the official traveller guidelines. There are several reasons why it ended up like this, and I don't know all of them. But two reasons I can think of: 1) With the introduction of RFID-based commuter cards, the zone system was revised for traditional ticket types as well. It appears convenient that a price can always be determined by knowing the check-in point, the check-out point and the shortest path in the graph. Unfortunately, with the old ticket types, you have to perform the calculation instead. 2) It is the odd shape of zone 2 that causes some tickets to not work on the way back, even though the trip goes in a straight line. But for a large part of all trips, you only need zone 1 and 2, or zone 2 and zone (30, 31, 32, 33). Only the ones that start in zone 2, go through zone 1, go back into zone 2 and farther into another zone (or vice versa) have the anomaly. (Trips that actually bend can have this too, but it is slightly more intuitive.)