@harry This sounds 100% like the 97 going Northwards from Stratford City when I used to try and catch it.
Keep up the good work!
OK, lets look each minute at the predictions for Stop 4 (GA, 490005183E): Balgonie Road
Where did SN63JVZ go?
Its vehicle prediction showed it as arriving at stop 4 at 09:10:49
But then no more:
until 09:12:11:
OK, so it’s now showing as being a couple of minutes later than previously expected.
But what happened between 09:04 and 09:12 to make the API think it should be telling everybody that this bus would not arrive at all?
That’s exactly the same as the 97 problem.
And it’s repeated with LX11BGU:
which disappears 1 minute later:
as does LX61DAA a couple of minutes later:
Then a new bus appears, but it’s not apparently coming for 27 minutes (despite this being a regular 7 minute service)
That’s still the only bus showing at 09:21:
when suddenly BGU reappears, with 0 minutes notice:
That’s not much help if you live 2 minutes from that bus stop, but were told there would be no bus for 25 minutes. It’s coming only a few seconds later than originally predicted ten minutes earler. But again, we need to find out why the API thought from 09:12 to 09:21 that it would not be coming at all.
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It’s now something like 9 months since I raised this problem but it appears not to have even been investigated. There is clearly something completely wrong with either the data coming from buses leaving the Chingford terminus or with what TFL is doing with that data when it presents it via the API and the countdown screens.
I initially thought it was a problem specific to 97, I’ve quoted evidence that it applies to other services, from different operators, on routes starting from Chingford. That includes at least 212, 197 and 313.
The predictions API, as currently implemented, is clearly completely unfit for its purpose, at least in respect of the first half dozen stops of buses starting from Chingford.
Could I please ask for a specific New Years Resolution, to get this unnecessary problem fully and properly investigated and fixed.
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hi @harry
Sorry for the delay in response to you.
The issue appears to be further down the stack than we can look at in the API. The API itself seems to be processing the data we receive from iBus/Countdown correctly, so we raised this with our colleagues who look after those systems.
This appears to be related to the iBus system’s use of 2G mobile network infrastructure. This is still under investigation with our colleagues in that area but the working theory is that coverage on 2G has been degraded across London by the cellular networks so that 4G & 5G services can be provisioned on existing towers. We have been doing analysis of our live vehicle tracking and working out the areas affected and the reliability of the data therein.
Again, I’m hoping to catch up with my colleagues on this matter this week and I’ll update the thread when I have some more information or updates from them.
Thanks,
James
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Thanks James.
Lack of 2G in the area seems like a fairly likely cause, but I’m surprised that iBus doesn’t have the capability of detecting lost transmissions in some way.
And if 2G is being deliberately degraded rather than just exhibiting occasional short term temporary faults, it’s strange that the networks haven’t confessed that to ofcom. Today it still thinks all four networks are providing OK voice coverage at Chingford Bus Station:
Of course, voice doesn’t mean 2G only and ofcom really ought to be providing separate columns for 2G and 3G. So I also checked at https://www.signalchecker.co.uk/ which has separate columns for “voice” and 3G, but that too claims good “non-3G” voice coverage indoors and outdoors for all four networks:
I also checked o2 coverage at https://status.o2.co.uk/ which specifically claims good 2G coverageindoors and outdoors (the blue covering the bus station (A) and all of the stops that aren’t getting proper predictions):
o2’s status checker does admit:
but it says that for all services, not specifically 2G.
Anyway, good to see it’s being looked into. I’m in the area about twice a week so I’ll quickly notice if any buses actually start being predicted to be less than 20 minutes away.
Has this been fixed? Several times in the last few days I’ve seen predictions in the Chingford area that for the first time in well over a year are properly showing buses arriving in the next 10 minutes. It seems to be a recent change – it was certainly as wrong as ever just a few weeks ago.
Was it the 2G problem, or something else?
Further checking shows the problem is not completely fixed. It seems that although the first bus on any route is now (usually) shown in the predictions, the second bus on the same route is often missing (but the third and fourth are usually correctly shown.
And yesterday I boarded a 97 bus that I spotted coming round the corner, despite the predictions showing nothing coming for 9 minutes:
Yet here it is at 15:10
and that was almost exactly when it had been predicted to arrive a few minutes earlier, but had mysteriously been dropped from the predictions:
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Thank you for your very detailed investigation into this. I am seeing this with several users where buses keep on disappearing and people are no longer trusting the system because buses just appear and disappear randomly. It seems to be increasing steadily as I am getting more and more complaints and I am unable to do such a thorough investigation like @harry did. Thank you!
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