Then they opened their APIs, and now I have a half dozen apps to choose from that will show the approximate time until the next bus from a particular line will reach any given stop.
(Not always 100% accurate, but useful enough to know when to wait indoors for 5 min if it's raining, or pick another line/choose to walk because of delays.)
That's all speculation though.
It's a tricky one, because they have big concerns about over-promising (e.g. the bus could be stuck behind an accident instead, in which case guessing that it's 5 minutes away because of past behaviour will really annoy people) so in some situations they err on the side of caution.
But they are unable to get rid of all of the corner cases. E.g. a bus that moves rapidly for a short stretch, then gets "stuck", will often appear, disappear, appear, disappear, with much less progress in time estimates than elapsed time should indicate.
The thing is, the team working on it has a huge amount of gathered info on how to give these predictions in a way that tries to minimise surprise and avoid making promises that cause problems for people. E.g. often it's better to take a bus off the list so people who are in a hurry will grab a taxi, rather than "promise" the bus will be there in just another few minutes. They still get it wrong too often, but I really don't envy them trying to get the right balance between promising too much and too little.
I don't know about London, I've seen some systems where the stops had "live-updating signs" but only provided the time of the next official passage. And while I wasn't clear, my bug is not just stop signage but phone access as well (that's most useful when e.g. it's raining cats and dogs and you want to avoid waiting in the rain at uncovered bus stops)
Apps like 'Transit' also (accurately) show the current GPS location of the bus as it approaches, and it updated every minute (I believe)
http://reisapi.ruter.no/Help/Api/GET-StopVisit-GetDepartures...
>Returns a List of StopVisits (departures) from a Stop. If no time parameter is supplied, departures in realtime will be returned.
Consider that e.g. in London the old route indicators on the buses used odometers. Which worked for telling you were along the route a bus was. Most of the time. But didn't tell you how long it takes until the bus reaches the next stop other than on average, as it would tell you nothing about traffic etc.
Today London buses don't use just GPS to replace it either, because that's nowhere near good enough. See the "Tracking" section here [1].
Even with all the extra data, and a lot number crunching, in London it's a challenge to get it to withing a few minutes during rush hour.
So, sure, if you're dealing with simple, small systems with little congestion, you can simplify.
We had that, through GPS + GPRS (or SMS?), back in 2001-2 in a small city I was living in Europe. Complete with full (flash based) website map of where each bus is.
I used it to get out of the tech park/institute I worked at and into the bus stop outside at the very last minute (since bus timetables where completely unreliable).
Displaying the actual bus status, though, is huge progress.
On some bus routes (and/or outside of peek times) you can pay a cash fare on the buss, but even that is still a single-use paper RFID card that should be tapped on and off. These sales are in the extreme minority though - the elderly require an electronic card to get their discount IIRC.
it is scalable because the bus-stop transmitters are added , moved, removed as needed.
updating the data can also be done remotely
These connections are in both the busses and the stops. The reason is so the stops can provide real time updates to people at the stops too. If a bus breaks down its no longer tracked on the real time updates so you are not effing and blinding because a the stop said there is a bus due in 5 mins and no bus comes. And if a bus is removed from service unexpected then the information on why can be feed to people waiting for the bus. People are less likely to be pissed that a bus didn't come when expected if they are given a valid reason.
Personally I was hoping they used some form of radio link I could of sniffed with a SDR so I could put a live updating sign in my house. I just scrape the data from their live feed they use to update the tracker on their mobile app/website instead.
Broadcasting out a signal from the stops could need a transmitter that may need to be licensed as the signal would be to be picked up quite a distance from the stop. Also not all the stops in my area are these "real time updating" stops as they are normally put into covered stops (EDIT: Bus Shelters... The correct term wouldn't come to mind while I was typing this.) and some of our stops are just poles in the ground with a sign on them. The busses tracking their own position wouldn't need these stops upgrading to give this information to people on board the bus as the covered stops can be quite a distance between each other and removes any issues if a stop get damaged and stops broadcasting data (say a car crashes into it).
The busses tracking themselves also have benefits that don't visibly benefit passengers. The services back office can monitor busses and spot problems on the network as they happen. Unexpected heavy traffic on a route may trigger the company to skip or stagger a bus (one of my local routes in advertised as being "every 5-10 mins". The real time traffic condition information could also be sold on to other companies (not sure on the value of this data esp for busses that run once an hour or even longer).
http://www.windytan.com/2013/11/decoding-radio-controlled-bu...
I would love to be able to talk to a tech at the travel network about this. My own research came to the suspicion that because where I am in the country they would of had to strike up deals with multiple transmission sites to get the coverage needed.
Also, there are things you want to do that this doesn't cover. For example, announcing the next stop when you pull away from the last stop.
(Lets ignore the security issues that have been shown with amplifying the low powered radio in cars for a second) It's a method used in keyless entry in cars. A higher powered radio is used for button press on the cars key so you can unlock the car/open the boot/sound the horn to locate the car at a distance but keyless unlock should only work at a much closer distance.
Not saying its the correct way to do it (my local bus network doesn't do this) but stop proximity can be worked into their idea.
I guess it is easier in the long run to have all routes mapped and instead of GPS you use something like doors open / doors close as a trigger to jump to the next entry.