Can anyone tell me how the digital displays at some London bus stops work?
The ones that estimate how long the next bus will take to get there? What
kind of connection are they maintaining with the bus etc? I'm very curious
how it works, I haven't seen that before.

any info appreciated,
John.

The system is called Countdown. It mainly works through a system called AVL
(Automatic Vehicle Location). This system uses transponders on the bus that
communicate with beacons stuck to lampposts along the route (little grey
boxes). This data gets sent to the home garage and then to the bus stops.
The arrival time is then worked out by comparing this data to the timetable.
I have heard rumours that this will be replaced by a GPS based system soon.

"john" wrote in message
...
Can anyone tell me how the digital displays at some London bus stops work?
The ones that estimate how long the next bus will take to get there? What
kind of connection are they maintaining with the bus etc? I'm very curious
how it works, I haven't seen that before.

any info appreciated,
John.

On Sat, 2 Aug 2003 17:59:03 +0100, "Richard Jeeves"
wrote:

The system is called Countdown. It mainly works through a system called AVL
(Automatic Vehicle Location). This system uses transponders on the bus that
communicate with beacons stuck to lampposts along the route (little grey
boxes). This data gets sent to the home garage and then to the bus stops.
The arrival time is then worked out by comparing this data to the timetable.
I have heard rumours that this will be replaced by a GPS based system soon.

"

Unlikely. London Buses did a technical review 18 months ago which
endorses the beacon approach.

The system which gives priority to buses at traffic lights is being
converted from inductive loop/transponder technology to beacons
progressively.

Rob.
--
rob at robertwoolley dot co dot uk

Along the bus route are beacons, as the bus passes these beacons a signal is
transferred from the bus to the beacon then to a central computer then to
the bus stop.
ice
"john" wrote in message
...
Can anyone tell me how the digital displays at some London bus stops work?
The ones that estimate how long the next bus will take to get there? What
kind of connection are they maintaining with the bus etc? I'm very curious
how it works, I haven't seen that before.

any info appreciated,
John.