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?)