RFID Månadskort

The public transportation system in Gothenburg is a mixture of busses, trams, trains and boats. Until a year ago they used a paper ticket system. Each card has a magnetic stripe. When you get on the bus, etc. you put the card in a big green box and punch the number for how many coupons to deduct. Inside Gothenburg it's 2 coupons for an adult. The box sucks the ticket in, deducts the money from the stripe, and prints the date, time, and remaining money. That's for the standard card, called a "hundra kronor kort" because it starts with 100 kronor on it.

From flickr: picture of the inside of a tram including the green ticket box. There are about 100 pictures there matching "gothenburg tram" and a few more for "spårvagn" (Swedish for "tram". It's composed of the words for "track" or "rail", and "vehicle". The nearest English cognate for "spår" is "spoor", as in an animal trail, and for "vagn" is "wagon".). Nearly all the flickr photos are shots of the outside. Admittedly, the trams look cooler from the outside.

There are other cards. The month, 3-month, 6-month (I think) and a one year card. These are time-based in that you can ride as many times as you want during the month for a fixed price. The first time one of these cards goes in the machine the machine records the time in ink and on the mag stripe. The next times it checks that the card is still valid.

That's changed. Last year they started putting in a new RFID system for the month card. See their web site if you can read Swedish or want to see the picture. They have a picture of the new box, which is blue instead of green. In the tram picture I linked to you can see the RFID box from the side (which is black). It's to the right of the green box.

The RFID system is supposed to be more convenient. When it works I take my wallet out and swipe it by the sensor. The light turns green and *poof*, that's it. Faster than the paper cards. The problem is in the failure modes. I've been using it for two weeks now and it's failed in several different ways. The most astonishing was when the blue box said I didn't have enough money. That's not supposed make a difference with a time-based card. All three boxes on the bus gave the same error message, so I assume there's a single controller for them. Also, the driver said the boxes were acting up all day. Another time one of the boxes didn't accept my card while another did, and yet another time none of the boxes accepted the card.

Those failure modes should disappear as bugs are worked out and the system is made robust. That's why this is a staged deployment.

There are other failure modes. The cards have no indication on them for when they were activated. The very first time I rode a bus in Sweden there was an inspector on the bus who checked everyone's ticket and made sure it was valid for the trip. That is, made sure it was properly time stamped (if a 100 kronor card) or within the date range (for time-based cards). If not, it's a fine.

Strange thing is in all the trips I've made since then I've never seen another inspector doing that. What made it worse is I was going to pay in cash but the ticket dispenser was broken so the driver couldn't sell me a ticket. He let me ride anyway. Hence I had no ticket for the inspector. I didn't know what was going on because the driver spoke no English. (In high likelihood he was an immigrant to Sweden.)

When I bought the RFID card the cashier said I needed to keep the receipt with the card. I assume so you have something to prove when you bought the card and hence if it's still valid. Two distinct items to carry is definitely more annoying than one. Someday if the 100-kronor cards also go RFID then there will be no paper evidence stating just how much money is on the card and how much was deducted for each transaction. For the date-based ones it's less of a problem but I'm leery of that possible future switch.

For now, the 100-kronor cards are paper-based.

I considered possible privacy implications of an RFID system over mag stripe. The only real difference is an RFID can be read from a distance while a mag stripe cannot. Otherwise, both could have a unique tag to them, used to track the card and are equally usable in a system which records when the same card was used for different trams. But the cards aren't tied to a person. I could have paid with cash. Plus, as I recall, the cards are transferable. You can give the month card to someone else. I assume the cost burden of sharing is factored into the cost of the card. (Unlike in Glasgow where even for a week card for their subway system they require the card have a photo id attached so it's tied to a single person.)

In dancing news, I went to Liseberg for salsa tonight. There was a woman toward the end who insisted on dancing with me. She saw that I do dips and had a different style than the others. She thought I danced New York style. She goes sometimes and thinks that's the best salsa there is. I'm an on-1 L.A. style, and I thought she danced more L.A. style than New York (which I thought was on-2). We had a few good dances and I dipped her a lot.

There are only two other people that I've seen here who dip. Lars-Olaf does the fancy ones, and there's a guy who's part of the rueda crowd who does some dips and I've seen him do a few basic aerials. (More than I can do, but less then the swing people do.)