"Roland Perry" wrote in message
...

If the arrival time says "10.35" that means the timetable says there
should be a bus at 10.35. Nothing more.

We have the sma problems in railway world... PIS pulls off the PTT and
assumes everything is ok. When a train is CAPD and the system is not told is
assumes its just not left yet, and either add's 2min's a time to its ETA.
Once it passes its due time at any point along the route (if it ever dose)
it will vanish without a trace.

If its delayed on leaving its origion then it will just rackup time by
2min's at every refresh, or if there is no recording of it it will vanish
anyway and show the next booked service, and then flup between the late one,
and the booked one.

If the arrival times says "3 minutes" that means they've tracked an actual
bus and it's 3 minutes away.

This is the same as 'LULTime' where in it might be 3 min's away, but not
moving - so it will never arrive in 3 min's


There is the added fun of turn-a-rounds at either end of the route, PIS (and
others) have no idea or concept of it, and can't compute the 'next working'
This can cause all sorts of fun when things go a bit broke.

What we should be doing with I-Bus is getting the backend to process what's
actually going on in real time based on live GPS data, LTIS, SWS, and real
time congestion data. They should have the ability to calculate the arrival
of the service at any given point based on all the information above. It
should also be aware of things like driver changes, and what happens when a
bus is pulled half way on its route.

In railway world all we need to do is process the TDS information a bit
better, work in turn-rounds, and have some hook into the SSI (Assuming we
don't role out a GPS system across the NR network...


My 2p worth.

On 12 Apr, 13:53, Tom Anderson wrote:

On Fri, 11 Apr 2008, MIG wrote:

Does the use of GPS have implications for Oyster and flat fares?

I don't think so. We had the technical capacity to have non-flat fares
before GPS, and indeed did so. The flares were flattened as an act of
policy, not practical exigency. I suppose with GPS they could introduce
some truly fiendish true-distance-based fare system, but i can't see why
they would.


That's not really right - it's a more complicated picture than you
paint and I think it's fair to say that the bus fares were flattened
as both an act of policy *and8 as a matter of practical exigency.
Making a smartcard system work on buses with a variable (i.e.non-flat)
fare structure introduces significant complications, in that either
passengers have some kind of transaction where they with specify the
length of their journey (whether with a driver or a machine) or
alternatively passengers need to touch-out at the end of their journey
before they alight from the bus. Or, I suppose, all bus stops are
fitted with Oyster readers ala Tramlink and passengers have to touch-
in and out on them.

I started a thread back in January on this very topic, and it contains
a very interesting, comprehensive and informative contribution from
Paul Corfield who was there in the early days of Oyster's development
and outlines some of the thinking that went on with regards to how to
make the smartcard system work on buses in London. He also shared his
experiences of how smartcards systems work on the transport systems of
Hong Kong and Singapore.

The thread is he
http://groups.google.co.uk/group/uk....a7d0d50c9d3b1/

For those who don't want to plough through all that, the most relevant
paragraph of what Paul C had to say with regards to the specific issue
of flat or variable fares on London's buses is this one:

"My guess is that the reality of making zonal fares work on buses
forced TfL into considering flat fares (although simplification had
been working its way through LT Buses for several years). This
consideration then meshed nicely with the aspirations of the Mayor to
drive up bus usage. The rest, they say, is history."

You're right in saying that GPS tracking (as part of the iBus project)
doesn't make any real difference to this whole issue - variable fares
are technically feasible without any such extra tracking technology.

I think that flat fares in London are here to stay, thankfully. I
don't think any future Mayor would dare change it, given the
tremendous advantage of quick boarding and thus reduction in dwell
time that it offers.

In message
, MIG
writes
On Apr 11, 6:52*pm, Tom Anderson wrote:
On Fri, 11 Apr 2008, Mizter T wrote:
On 11 Apr, 17:20, MarkVarley - MVP
wrote:

I have no idea what they're called, the LED signs in some bus stops
that tell you how long the busses are supposed to be, my question is,
how do they work? how do they update?

The system is called Countdown, and as part of the iBus project it is
set to become much more reliable and accurate.

Which is a roundabout way of saying that the present system is not very
reliable or accurate :P.

As another poster pointed out, the present system is rather Heath-Robinson
and failure-prone. It was, though, the best that could be done with the
technology of the time it was implemented. Frustrating as it is, it's
better than nothing.

Was it a development of the BESI system used in the 1970s?

There was something else between BESI and Countdown and I can't for the
life of me remember what it was and can't be bothered to Google.
Someone will tell me any time now.......
--
Ian Jelf, MITG
Birmingham, UK

Registered Blue Badge Tourist Guide for London and the Heart of England
http://www.bluebadge.demon.co.uk

On Apr 12, 11:55*am, Mizter T wrote:
On 12 Apr, 10:36, Roland Perry wrote:





In message , at 17:20:26 on
Fri, 11 Apr 2008, MarkVarley - MVP
remarked:

A few times I've seen that my bus is due next in a couple of minutes
but it just doesn't arrive, several later busses come and then it
vanishes off the sign, abducted by aliens?

Signs like that normally have two modes of operation (but they fail to
explain this).

If the arrival time says "10.35" that means the timetable says there
should be a bus at 10.35. Nothing more.

If the arrival times says "3 minutes" that means they've tracked an
actual bus and it's 3 minutes away.

The former will just scroll off irrespective of the passage of buses.

I'm almost certain that the London Countdown system doesn't have any
capability to work in the first way you describe - i.e. by simply
listing buses according when they should arrive according to the
timetable.-

I am sure that the disappearance is due to the locations of detectors
and faster than expected arrivals. Eg if the nearest detector is in a
location deemed to be 10 minutes away, and the bus does it in 7
minutes, it will show the bus as still expected for 3 minutes after
it's gone. (Although could the detectors be that far apart?)

On Apr 12, 4:46*pm, Ian Jelf wrote:
In message
, MIG
writes





On Apr 11, 6:52*pm, Tom Anderson wrote:
On Fri, 11 Apr 2008, Mizter T wrote:
On 11 Apr, 17:20, MarkVarley - MVP
wrote:

I have no idea what they're called, the LED signs in some bus stops
that tell you how long the busses are supposed to be, my question is,
how do they work? how do they update?

The system is called Countdown, and as part of the iBus project it is
set to become much more reliable and accurate.

Which is a roundabout way of saying that the present system is not very
reliable or accurate :P.

As another poster pointed out, the present system is rather Heath-Robinson
and failure-prone. It was, though, the best that could be done with the
technology of the time it was implemented. Frustrating as it is, it's
better than nothing.

Was it a development of the BESI system used in the 1970s?

There was something else between BESI and Countdown and I can't for the
life of me remember what it was and can't be bothered to Google.
Someone will tell me any time now.......

I can't find much about it at all, but I've seen pictures of "radio-
controlled" buses in the 1970s passing some kind of scanners in the
street. (It stood for "Bus Electronic Scanning Indicator"?)

It would have been used for managing buses, but I suppose that once
you've got a system for locating and identifying buses, the next stage
is to link the information to PIS.

Would the system in between have been perfecting the management part,
or would it be to do with the PIS part?

On Fri, 11 Apr 2008 11:22:49 -0700 (PDT), MIG
wrote:

Does the use of GPS have implications for Oyster and flat fares?

Not under the current Mayoral regime as I don't see Ken removing flat
fares.

However I think GPS or something similar is used in Singapore to
determine bus position relative to bus stops and this triggers the card
readers to become active and able to read and write to cards. This is
because Singapore has entry and exit validation on bus. Works very well
to be honest but that's as much a cultural phenomenon as a technological
one. TfL are proposing a new form of bus ticket machine that will act
as a technology hub linked into new radio and I-Bus. There is some
mammoth document on the TfL website that lists all of the projects in
the next Business Plan and this is in it. It could form the backbone of
allowing exit validation and distance based charging.

If you were feeling particularly nasty you could infer that the lack of
mention of fares policy in Boris's manifesto and the proposed
reintroduction of conductors could presage a return to some form of
distance based fare in London. On the face of it Mr Paddick's "I hour
and as many changes as you like" ticket must presumably be flat within
whatever area it applies in. From what little I've read about it that
policy was off the back of shortening routes that run in to Zone 1 and
forcing people to change buses - a recipe for failure if ever I read one
given the long established travel patterns on core routes into Zone 1.

--
Paul C


Admits to working for London Underground!

On Sat, 12 Apr 2008 07:14:04 -0700 (PDT), Mizter T
wrote:

I think that flat fares in London are here to stay, thankfully. I
don't think any future Mayor would dare change it, given the
tremendous advantage of quick boarding and thus reduction in dwell
time that it offers.

Given how simplistic the policies are from the other mayoral candidates
I fear your thoughts may be misplaced. As they understand so little
about how transport works in the capital and are making easy promises
I'd guess they believe they have "easy" options with regards to fares
when they face a financial squeeze and decide to increase them. Child
fares will be the first to return and then we'll have different fares
for express routes, different fares for conductor buses because they're
"better" but cost more to run and then longer routes are more expensive
to run so we need to charge more .....
--
Paul C


Admits to working for London Underground!

On Sat, 12 Apr 2008 14:07:54 +0100, Tom Anderson
wrote:

On Fri, 11 Apr 2008, Paul Corfield wrote:

On Fri, 11 Apr 2008 13:54:58 -0700 (PDT), Mr Thant
wrote:

The other was the system seeming to be completely dead and then suddenly
springing into life after leaving a stop. I have no idea how GPS works
but if it uses any form of cellular pattern to locate a vehicle I did
wonder if we had crossed from one cell to another in the second example.

It doesn't. Unlikely as this may sound, it works by picking up
synchronised radio signals from members of a family of 31 satellites
orbiting 20 000 km above the earth, measuring the time differences between
them with an accuracy of a few nanoseconds, which tells you the
differences in distances to the satellites with an accuracy of a few
metres (out of twenty million - not bad!), then doing geometric
calculations to work out where that means the receiver must be. It's the
kind of thing that if it didn't exist, you'd think it was an absurd idea.
A bit like the London Underground!

Working out your position depends on being able to pick up the signals
from the satellites, and buildings and other features of cities can
interfere with this. I suspect the jumpiness is caused by this: if the bus
has lost the signal for a moment, it won't fire off its announcement until
it's picked it up again and worked out where it is.

Thanks for the technical explanation - what was odd about the example I
witnessed was that we'd just crossed the Lea Valley reservoirs where
there are no tall buildings for miles and the bus is fully exposed to
the sky so had every chance to receive its signals over a longish
distance. Still it was the first installation so perhaps it was just
one in a long series of bugs.
--
Paul C


Admits to working for London Underground!

On Sat, 12 Apr 2008 16:46:02 +0100, Ian Jelf
wrote:

In message
, MIG
writes

Was it a development of the BESI system used in the 1970s?

There was something else between BESI and Countdown and I can't for the
life of me remember what it was and can't be bothered to Google.
Someone will tell me any time now.......

PIBS? Passenger Information at Bus Stops.
--
Paul C


Admits to working for London Underground!

On 12 Apr, 19:06, Paul Corfield wrote:
Thanks for the technical explanation - what was odd about the example I
witnessed was that we'd just crossed the Lea Valley reservoirs where
there are no tall buildings for miles and the bus is fully exposed to
the sky so had every chance to receive its signals over a longish
distance. *Still it was the first installation so perhaps it was just
one in a long series of bugs.

Might be that the programmed positions of the stops was off:
http://www.tfl.gov.uk/assets/downloa...tions_v00e.pdf

(long paper on TfL trying to figure out exactly where there bus stops
are)

U

--
http://londonconnections.blogspot.com/
A blog about transport projects in London