How do TfL work out the off peak journey times for timetables?

[infobleep]

I'm doing a journey that is meant to take 43 minutes but it's looking increasing like it's going to take longer.

I did read that there was a move to publish bus delay data. This would be useful. I had two choices. 213 or X26. 213 is more frequent but the X26 is faster 10 minutes faster. As a 213 was due and it was roughly 10 minutes in advance of the X26, I decided to catch it. Needless to say the X26 overtook me on route and not right at the end of the journey either!

Also useful would be more data than just the next 30 minutes. If your on a bus journeyof over 30 minutes it would be useful to know the estimated arrival time. This might be wrong but at lest you'd see the route ahead, where as now it's. Ugh harder to see the route ahead.

What I'm asking for may exist and it could be a limitation of London Bus Checker all I use. I don't actually know. I suspect not.

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[paddington]

Traffic in London is so unreliable that they can't do much more than guess. Taking buses in London is like an art.

 

[matt_world2004]

I'm doing a journey that is meant to take 43 minutes but it's looking increasing like it's going to take longer.

I did read that there was a move to publish bus delay data. This would be useful. I had two choices. 213 or X26. 213 is more frequent but the X26 is faster 10 minutes faster. As a 213 was due and it was roughly 10 minutes in advance of the X26, I decided to catch it. Needless to say the X26 overtook me on route and not right at the end of the journey either!

Also useful would be more data than just the next 30 minutes. If your on a bus journeyof over 30 minutes it would be useful to know the estimated arrival time. This might be wrong but at lest you'd see the route ahead, where as now it's. Ugh harder to see the route ahead.

What I'm asking for may exist and it could be a limitation of London Bus Checker all I use. I don't actually know. I suspect not.

Sent from my SM-G925F using Tapatalk

They use the average journey time data from ibus while chopping off the 10% slowest and fastest journeys for that trip. This allows the timetable to factor in local factors that cause delays (for example if one trip is longer caused by a local school. That will be factored into the timetable. ) However it often means that if a bus is typically carting fresh air (for example an in service depot move ) it means that if one passenger boards it can delay the service.

The average London bus was delayed 1.2 minutes in the last three months

 

[infobleep]

They use the average journey time data from ibus while chopping off the 10% slowest and fastest journeys for that trip. This allows the timetable to factor in local factors that cause delays (for example if one trip is longer caused by a local school. That will be factored into the timetable. ) However it often means that if a bus is typically carting fresh air (for example an in service depot move ) it means that if one passenger boards it can delay the service.

The average London bus was delayed 1.2 minutes in the last three months

Thanks that's really interesting.

I've worked out roughly how long on average some bus journeys should be but for new ones I rely on the figures they quote.

The 213 is a high frequency bus, every 7-12 during the day, so is busy. The X26 only runs every half an hour. So I choose frequency over speed as I felt we'd arrive much the same time, based on when I left Kingston. I was wrong.

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[plcd1]

I'm doing a journey that is meant to take 43 minutes but it's looking increasing like it's going to take longer.

I did read that there was a move to publish bus delay data. This would be useful. I had two choices. 213 or X26. 213 is more frequent but the X26 is faster 10 minutes faster. As a 213 was due and it was roughly 10 minutes in advance of the X26, I decided to catch it. Needless to say the X26 overtook me on route and not right at the end of the journey either!

Also useful would be more data than just the next 30 minutes. If your on a bus journeyof over 30 minutes it would be useful to know the estimated arrival time. This might be wrong but at lest you'd see the route ahead, where as now it's. Ugh harder to see the route ahead.

What I'm asking for may exist and it could be a limitation of London Bus Checker all I use. I don't actually know. I suspect not.

Sent from my SM-G925F using Tapatalk

I assume you mean how does I-Bus handle real time data rather than what the schedules say?

TfL do now publish the detailed schedules for every TfL contracted service so you can at least see the scheduled time for every journey in the operating day.

https://tfl.gov.uk/corporate/publications-and-reports/bus-schedules

In terms of real time data then TfL have a cut off at 29 minutes for the data and that translates into the public feed that drives apps. I agree it would make sense to have a wider window even if only by 5-6 mins given many night and some outer area buses run at x30 intervals.

I'll defer to what MattWorld has said about how expected arrival times are calculated. I am probably wrong but I understood there was some clever algorithm inside I-Bus that tracked the time each bus takes along a route and then compares in real time how the bus you're waiting for is running relative to the inter stop speeds for the two previous buses on the route. This means it slows down or speeds up the time a bus takes relative to the prevailing traffic conditions. Obviously it's not perfect given there are so many reasons why a bus may be slow or may not move as expected (lots of people at a stop, a minor traffic incident delaying a bus, a wheelchair passenger wishing to board and buggies having to be moved etc etc).

I-Bus also has the ability to advise drivers of their time keeping relative to headway (for high frequency routes) or timetable (for low freq ones). The system certainly knows where every bus should be relative to the contracted schedule. That info is shared across various TfL systems and operators have to supply their schedules in a defined format to be used by those systems.

 

[infobleep]

I assume you mean how does I-Bus handle real time data rather than what the schedules say?

TfL do now publish the detailed schedules for every TfL contracted service so you can at least see the scheduled time for every journey in the operating day.

https://tfl.gov.uk/corporate/publications-and-reports/bus-schedules

In terms of real time data then TfL have a cut off at 29 minutes for the data and that translates into the public feed that drives apps. I agree it would make sense to have a wider window even if only by 5-6 mins given many night and some outer area buses run at x30 intervals.

I'll defer to what MattWorld has said about how expected arrival times are calculated. I am probably wrong but I understood there was some clever algorithm inside I-Bus that tracked the time each bus takes along a route and then compares in real time how the bus you're waiting for is running relative to the inter stop speeds for the two previous buses on the route. This means it slows down or speeds up the time a bus takes relative to the prevailing traffic conditions. Obviously it's not perfect given there are so many reasons why a bus may be slow or may not move as expected (lots of people at a stop, a minor traffic incident delaying a bus, a wheelchair passenger wishing to board and buggies having to be moved etc etc).

I-Bus also has the ability to advise drivers of their time keeping relative to headway (for high frequency routes) or timetable (for low freq ones). The system certainly knows where every bus should be relative to the contracted schedule. That info is shared across various TfL systems and operators have to supply their schedules in a defined format to be used by those systems.

That's for the interesting reply. As I can't see beyond 30 minutes I couldn't see what my estimated arrival time would be at my destination so relied upon the off peak timings TfL provide online. I'd have preferred to use the real time estimate.

I think the off peak estimate isn't any use for regularly travelling in the peak. The peak could of course be more volatile. Perhaps they could calculate a range in which your bus might arrive and depart. The data us being collected so it would require some maths.

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[matt_world2004]

I assume you mean how does I-Bus handle real time data rather than what the schedules say?

TfL do now publish the detailed schedules for every TfL contracted service so you can at least see the scheduled time for every journey in the operating day.

https://tfl.gov.uk/corporate/publications-and-reports/bus-schedules

In terms of real time data then TfL have a cut off at 29 minutes for the data and that translates into the public feed that drives apps. I agree it would make sense to have a wider window even if only by 5-6 mins given many night and some outer area buses run at x30 intervals.

I'll defer to what MattWorld has said about how expected arrival times are calculated. I am probably wrong but I understood there was some clever algorithm inside I-Bus that tracked the time each bus takes along a route and then compares in real time how the bus you're waiting for is running relative to the inter stop speeds for the two previous buses on the route. This means it slows down or speeds up the time a bus takes relative to the prevailing traffic conditions. Obviously it's not perfect given there are so many reasons why a bus may be slow or may not move as expected (lots of people at a stop, a minor traffic incident delaying a bus, a wheelchair passenger wishing to board and buggies having to be moved etc etc).

I-Bus also has the ability to advise drivers of their time keeping relative to headway (for high frequency routes) or timetable (for low freq ones). The system certainly knows where every bus should be relative to the contracted schedule. That info is shared across various TfL systems and operators have to supply their schedules in a defined format to be used by those systems.

There is, a way of drivers keeping relative to their headway and for measuring their approach time to a stop

I asked a planner at tfl how they plan timetables, today. They don't in the invitation to tender document, they specify frequency per hour, TfL then provide ibus data for three month non school holiday period together with a list of challenges that may effect the route reliability eg

"Regular football matches at Queens Park"

the route is then sometimes bundled with another route, that has a low PVR and a different peak time period (for example a school route might be bundled with a bus route whose peak time period is defined by shoppers)

TfL specifies what type of fleet to use, eg NBFL , 87 capacity Double Deck, 45 capacity double door single deck, how many miles the route is expected to run

The operator then provides an timetable and running time based on this data , If there is too much padding without valid reason tfl can reject the contract or ask for a revision if the running time seems impossible to match likewise,
The operator also specifies fleet size, rosters and a cost of operating the route over 5 years,

 

[Busaholic]

There is, a way of drivers keeping relative to their headway and for measuring their approach time to a stop

I asked a planner at tfl how they plan timetables, today. They don't in the invitation to tender document, they specify frequency per hour, TfL then provide ibus data for three month non school holiday period together with a list of challenges that may effect the route reliability eg

"Regular football matches at Queens Park"

the route is then sometimes bundled with another route, that has a low PVR and a different peak time period (for example a school route might be bundled with a bus route whose peak time period is defined by shoppers)

TfL specifies what type of fleet to use, eg NBFL , 87 capacity Double Deck, 45 capacity double door single deck, how many miles the route is expected to run

The operator then provides an timetable and running time based on this data , If there is too much padding without valid reason tfl can reject the contract or ask for a revision if the running time seems impossible to match likewise,
The operator also specifies fleet size, rosters and a cost of operating the route over 5 years,

I wonder how long this system will remain viable for. Increases in road traffic, accompanied inexorably by decrease in bus speeds, are not about to go away, and traffic measures like cycle lanes and 20 mph speed limits only exacerbate the problem. Almost all increases in the number of buses operated in London now are due to increases in running time, so no better level of service is supplied: conversely, other routes get running time increases without an extra bus or two, so headway gets cut. Services with a headway of less than 10 minutes are particularly prone to being cut, sometimes on a supposedly 'temporary' basis, but then the introduction of Income Tax was a temporary measure. Some inner London routes have had BPH cut by a third in peaks over the last couple of years, usually in two or three stages.

 

[matt_world2004]

I wonder how long this system will remain viable for. Increases in road traffic, accompanied inexorably by decrease in bus speeds, are not about to go away, and traffic measures like cycle lanes and 20 mph speed limits only exacerbate the problem. Almost all increases in the number of buses operated in London now are due to increases in running time, so no better level of service is supplied: conversely, other routes get running time increases without an extra bus or two, so headway gets cut. Services with a headway of less than 10 minutes are particularly prone to being cut, sometimes on a supposedly 'temporary' basis, but then the introduction of Income Tax was a temporary measure. Some inner London routes have had BPH cut by a third in peaks over the last couple of years, usually in two or three stages.

Funnily enough the representative of a bus company I was with said exactly the same today.

 

[Deerfold]

The average London bus was delayed 1.2 minutes in the last three months

Is that not the Excess Wait Time? If it is, that means the average wait for a bus in London was 1.2 minutes longer than you'd expect from the timetable, meaning the average bus can be delayed an awful lot more than that.

If they've got the average bus delay down to 1.2 minutes, someone's been working miracles.

 

[plcd1]

That's for the interesting reply. As I can't see beyond 30 minutes I couldn't see what my estimated arrival time would be at my destination so relied upon the off peak timings TfL provide online. I'd have preferred to use the real time estimate.

I think the off peak estimate isn't any use for regularly travelling in the peak. The peak could of course be more volatile. Perhaps they could calculate a range in which your bus might arrive and depart. The data us being collected so it would require some maths.

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I'm assuming you don't know about London Vehicle Finder. If you do then apologies for "teaching you to suck eggs".

If you use the London Vehicle Finder website then you can type in an instruction to see the forward prediction of the vehicle you are travelling in or even a vehicle you think will connect to on another route.

LVF is at https://lvf.io

You can enter a stop code or a route number of a vehicle ID. The site is really designed for people to find particular vehicles so you can also search by registration and also fleet number (incl company code).

If you search by route number you will get the current position of all vehicles on the route.

If you search by stop code you will get the next 29 mins worth of departures.

If you enter eta company code vehicle code then you will get the expected progression of that vehicle for the next 29 minutes.

For example "eta al vla1" (no quotes needed) would show you the expected progression of Arriva London's VLA1 bus. Obviously if the vehicle is not moving (on a stand) or out of service or not transmitting then you may get a nil return. Sometimes buses on stands will keep transmitting so you'll see the expected departure time from the stand and then however minutes until the 29 min window closes (e.g. if bus is due out in 10 mins then you'd get 19 mins worth of journey time and the stops expected to be reached).

I can confirm that the eta function in lvf can be very useful if you need to make a connection. Equally it can be frustrating if it confirms you've missed the connection for some reason.

You do need to be consider that buses can "disappear" if controllers take them off service to run light to make up time or if buses conk out or if they are simply going off service as expected. In short the data is never 100% accurate for legitimate reasons.
--- old post above --- --- new post below ---

Is that not the Excess Wait Time? If it is, that means the average wait for a bus in London was 1.2 minutes longer than you'd expect from the timetable, meaning the average bus can be delayed an awful lot more than that.

If they've got the average bus delay down to 1.2 minutes, someone's been working miracles.

Not really. It was 1.0 a couple of years before the traffic was completely screwed by never ending road works and other issues. A network EWT of 1.2 is the worst result for several years - the TfL target was, I think, 1.1 for the last financial year so they failed to meet their own target despite increasing PVRs, reducing frequencies and curtailing some services. It's a monumental mess with little sign of any improvement in this aspect of performance nor of ridership (based on the period figures released so far this year).

 

[infobleep]

Thanks I'd not head of that Web Site until now.

For short journeys, sometimes it's quicker or almost as quick to walk than get the bus or the bus will only save you 3-5 minutes. Fine if you have a connection to make.

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[Deerfold]

Not really. It was 1.0 a couple of years before the traffic was completely screwed by never ending road works and other issues. A network EWT of 1.2 is the worst result for several years - the TfL target was, I think, 1.1 for the last financial year so they failed to meet their own target despite increasing PVRs, reducing frequencies and curtailing some services. It's a monumental mess with little sign of any improvement in this aspect of performance nor of ridership (based on the period figures released so far this year).

I think you may have missed my point. I was suggesting that this figure is not the average amount a bus is delayed by. If it was the amount a bus was delayed by then it would be a great figure.

If it's EWT then it is getting worse. I used to work on iBus which now produces these figures and the figures were usually 1.0 or 1.1 for the network as a whole.

 

[plcd1]

I think you may have missed my point. I was suggesting that this figure is not the average amount a bus is delayed by. If it was the amount a bus was delayed by then it would be a great figure.

If it's EWT then it is getting worse. I used to work on iBus which now produces these figures and the figures were usually 1.0 or 1.1 for the network as a whole.

OK fair enough.

 

[matt_world2004]

Is that not the Excess Wait Time? If it is, that means the average wait for a bus in London was 1.2 minutes longer than you'd expect from the timetable, meaning the average bus can be delayed an awful lot more than that.

If they've got the average bus delay down to 1.2 minutes, someone's been working miracles.

Yes sorry I was trying to simplify ewt a bit while writing in mobile.

 

[Busaholic]

Funnily enough the representative of a bus company I was with said exactly the same today.

Great minds think alike (I won't continue with the rest)

 

[londonbridge]

The 213 is a high frequency bus, every 7-12 during the day, so is busy. The X26 only runs every half an hour. So I choose frequency over speed as I felt we'd arrive much the same time, based on when I left Kingston. I was wrong.

Don't forget the X26 is an express/limited stop route, the 213 is not. Also the X26 turns off at Cambridge Road and goes directly to The Fountain roundabout, whilst the 213 goes off on a detour through Norbiton/Coombe and along New Malden High Street.

 

[infobleep]

Don't forget the X26 is an express/limited stop route, the 213 is not. Also the X26 turns off at Cambridge Road and goes directly to The Fountain roundabout, whilst the 213 goes off on a detour through Norbiton/Coombe and along New Malden High Street.

I'm aware of that but the public timetable timings of them meant the 213 would have been a better bet. Not so that day.

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[AndyNLondon]

Increases in road traffic, accompanied inexorably by decrease in bus speeds, are not about to go away, and traffic measures like cycle lanes and 20 mph speed limits only exacerbate the problem.

Just to pick up on these points:

A good quality separated cycle lane can easily improve bus journey times, because it will reduce the occasions when buses are held up behind cyclists. (Consider a standard-width bus lane. It's not wide enough for a bus to overtake a cyclist without the bus pulling out into the adjacent general-traffic lane, with two possibilities: either the bus is held up behind the cyclist, or traffic in the adjacent lane is flowing freely enough that the bus can overtake easily.)

And I doubt there are many London bus routes where buses regularly reach 30mph on roads which would be likely to get a 20mph limit. (E.g. even with "borough-wide" 20mph limits that some London boroughs have introduced, these tend to exclude main road managed by TfL.) To use the 213 as an example, the route is just over 8 miles and is scheduled to take 52 mins, for an average of approx 9mph. Let's assume that buses run at 30mph for 4 of those 8 miles (which would mean it's barely averaging 5mph for the rest of the route), and that the roads where that 30mph running happens were all to get 20mph limits: that would add a whopping 4 minutes to the journey time. (At 30mph a mile takes 2 mins, at 20mph it takes 3.)

 

[Busaholic]

Just to pick up on these points:

A good quality separated cycle lane can easily improve bus journey times, because it will reduce the occasions when buses are held up behind cyclists. (Consider a standard-width bus lane. It's not wide enough for a bus to overtake a cyclist without the bus pulling out into the adjacent general-traffic lane, with two possibilities: either the bus is held up behind the cyclist, or traffic in the adjacent lane is flowing freely enough that the bus can overtake easily.)

And I doubt there are many London bus routes where buses regularly reach 30mph on roads which would be likely to get a 20mph limit. (E.g. even with "borough-wide" 20mph limits that some London boroughs have introduced, these tend to exclude main road managed by TfL.) To use the 213 as an example, the route is just over 8 miles and is scheduled to take 52 mins, for an average of approx 9mph. Let's assume that buses run at 30mph for 4 of those 8 miles (which would mean it's barely averaging 5mph for the rest of the route), and that the roads where that 30mph running happens were all to get 20mph limits: that would add a whopping 4 minutes to the journey time. (At 30mph a mile takes 2 mins, at 20mph it takes 3.)

As I have no 'inside information' as it were I don't know why new timetables/running times are now quoting 'implementation of 20 mph zones' as being a reason given, often with an extra bus or two added if headways are to be maintained, but my assumption was always that it was the (hoped-for) general decrease in speeds of other road users that would impinge on the speed of buses, not that would-be Lewis Hamiltons in the busdriving community were being reined in!

Cycling is a good thing, most would agree, and provision must be made for the activity. Maybe I'm jaundiced through having lived in Amsterdam (a long time ago) but I find most cycle schemes I've come across in the UK to be half-baked, not well thought out at all with all road users in mind (including pedestrians, the most important of all) and some so dangerous imo they should be immediately scrapped. Regrettably, some in London I'd put into the latter category.

 

[greatkingrat]

Not really. It was 1.0 a couple of years before the traffic was completely screwed by never ending road works and other issues. A network EWT of 1.2 is the worst result for several years - the TfL target was, I think, 1.1 for the last financial year so they failed to meet their own target despite increasing PVRs, reducing frequencies and curtailing some services. It's a monumental mess with little sign of any improvement in this aspect of performance nor of ridership (based on the period figures released so far this year).

That is only an increase of 12 seconds, hardly a complete disaster.

 

[Deerfold]

That is only an increase of 12 seconds, hardly a complete disaster.

That's an increase of 12 seconds for every bus between every stop (on average). That adds up to a lot. For a typical route with 25 stops that's an extra 5 minutes.

As it's an average it's unlikely to be evenly spread through the day. So how much longer is each peak time bus taking?

Also, bear in mind that a natural side-effect of extra buses being added to the network is the reduction of EWT. We're adding buses to the network but still seeing EWT go up - so the increase is on top of negating the positive effect of those extra buses.

 

[plcd1]

That is only an increase of 12 seconds, hardly a complete disaster.

No one said that it was a *complete* disaster. What is clear from TfL's own commentary and the disastrous plunge in patronage and bus revenue that traffic congestion and delays are a serious issue. In barely 18 months the former Mayor and TfL managed to reverse well over a decade's progress in growing patronage and income on London's bus network and sustaining a change in modal share towards public transport. TfL have had to try to explain the facts - tens of millions fewer pass jnys on buses and tens of millions of quid lower revenue. Can't get away from that.

Worse I've just checked this year's numbers so far in the London Datastore. So far (periods 1-4) bus pass jnys are down 34m compared to last year. That must be causing real concern as there's no clear sign of any recovery which is what TfL predicted when the major road works in Central London finished.

 

[Busaholic]

That's an increase of 12 seconds for every bus between every stop (on average). That adds up to a lot. For a typical route with 25 stops that's an extra 5 minutes.

As it's an average it's unlikely to be evenly spread through the day. So how much longer is each peak time bus taking?

Also, bear in mind that a natural side-effect of extra buses being added to the network is the reduction of EWT. We're adding buses to the network but still seeing EWT go up - so the increase is on top of negating the positive effect of those extra buses.

I believe we now have the first case of a 24 hour bus route, the 35, where the Friday/Saturday night frequency over part of the route is better than its daytime frequency, even peak hours. The 29/N29 offers a similar scenario.