I don’t know where or when timetables have started appearing at tram stops, but I know that they are useful. They serve the double aim of informing passengers about the schedule and reassuring them that their tram will come soon.
A good timetable is precise, easy to navigate, and contains the exact information required by the traveller. An excellent timetable might even include phone number to call in case of questions or to leave feedback on the service. An extraordinary timetable has estimated travel time between stops and information about disruptions to service or delays.
Since coming across and reading in detail Yarra Trams’ timetable for tram number 86 (Waterfront City to Bundoora) I have been trying to imagine the usability principle that has guided its design. An attentive examination of the timetable will reveal some challenges.
The first tram to arrive at Stop 20 Rose St & Smith St is the 6:15, and up until the 7:54 tram, every single tram arrival is listed in the timetable. Then, at 8:00 am, something happens: no times of arrival but only frequency until 8:00 pm.
This timetable presents several flaws.
First of all it is impossible to calculate the time of the trams after 7:54 because the timetable from there only states ‘every 10 minutes’ without explaining whether it is 10 minutes from the previous 7:54 am service (= 8:04 am) or 10 minutes from 8:00 am (= 8:10 am), in proximity of the ‘every 10 minutes’ line.
The calculation becomes more complicated and increasingly impossible as the timetable reaches the afternoon: any traveller wishing to know the estimated arrival time, must go back to the 7:54 am service and add values until reaching the desired timeslot.
Since coming across this timetable, I have been wondering about its impact on travellers. Unless being a trained arithmeticians accustomed at performing long calculations on the spot, most people will feel a sense of frustration and some people will feel cheated (“Why bother with a timetable if you don’t tell me at what time it’s coming?”). But there is a third category that will be pervaded by a sense of relieved, finally liberated from the fear of having missed the tram.
Paraphrasing a wise Buddhist proverb, there is no tram to be missed if you never know whether the tram is coming.