What causes later bus stops to show up before earlier bus stops on live timings

[infobleep]

Does anyone know what causes a later Transport for London bus stop to show before an earlier one in the live timings?

For example, today I noticed that Kingston-by-pass Hinchley Wood was showing after Hinchley Wood Station. Yet on the route to Roehampton it is in fact first. The timings said the bus would arrive at the station stop at 08:29 and the by-pass stop at 08:30.

Here are a couple of screenshots from my Bus Countdown app. The first shows the stops the wrong way round and the second shows them the right way round.



I know it updates correctly when nearing the stop. I was just interested, from a technical stand point, as to what causes them to be out in the first place.

 

[Deerfold]

Thanks. I accidentally brushed past send earlier whilst a passenger was getting off the bus as I had to move, so I'd not actually finished writing my post.

Here is a couple of screenshots from my Bus Countdown app. The first shows the stops the wrong way round and the second shows them the right way round.

View attachment 66459 View attachment 66460

I know it updates correctly when nearing the stop. I was just interested, from a technical stand point as to what causes them to be out in the first place.

What app are you using? It may be a fault with the app.

 

[infobleep]

What app are you using? It may be a fault with the app.

I'm using Bus Countdown. It may also go under another name but that is the name of the installed app icon. It could well be due to how they estimate the bus arrival times, although I thought that was done by TfL.

 

[Darklord8899]

I suspect that it may be due to the fact that there is vast amounts of data being sent back and forward and being processed, along with variances in GPS tracking, resulting in the inevitable glitch occurring, GPS reporting a vehicle slightly ahead/behind where it actually is.

I've noticed when looking at the tracking map for Edinburgh a bus apparently travelling along in the water of Leith, then taking a left turn through a large ASDA superstore and a cemetery before rejoining the road..... Clearly the vehicle in question didn't actually do this!

 

[Deerfold]

I'm using Bus Countdown. It may also go under another name but that is the name of the installed app icon. It could well be due to how they estimate the bus arrival times, although I thought that was done by TfL.

That is done by TfL. A new time is estimated every 30 seconds. The app will ask for the predicted times at all stops on the route. It's possible that if the estimates are updated halfway through the request (and they get earlier) then the estimates received may put the bus at stops in the wrong order.
TfL does provide the sequence of stops on the route. This cannot change midway through a day. It looks like your app does not use this sequence data, but relies on the estimates being in the right order.
I used to work at TfL, collecting data from the API used by apps and comparing it to other data to find and rectify mistakes.