[dcw303]

Where is the data sourced from? I ask because of an experience I had recently when visiting Sydney. I was using transportnsw.info while waiting at a stop at Wynyard.

Eventually it told me that the bus I was waiting for had been and left, which seemed odd because I could see it still sitting idle further down the street. It eventually pulled up to the terminal about five minutes late, but the app did not update to reflect this.

[contingencies]

AFAIK a lot of dated bus systems have radio polling is based on signal loss. Under such a system, a stop sends out a weak stop-ID signal. If buses sit around the periphery of natural propagation they may 'drop in' and 'drop out' of a stop prematurely, which can trigger false readings. Unsure if that's how Sydney runs. Most systems now use GPS which is also susceptible to drift if not properly written (probably common). FWIW I had prior exposure to the RTA's traffic management systems in Redfern (PDP-11 still running!) ~2001, which also housed the State Emergency Service (SES) wireless system, but AFAIK no public transport.

[bogantech]

Sydney buses have had GPS and open data for several years, at least as far back as 2012 iirc.

My employer at the time was contracted for part of that project but I wasn't really involved and barely remember anything that long ago.

https://www.zdnet.com/article/real-time-tracking-of-sydney-b...

[contingencies]

Simply having GPS doesn't mean it is used for station arrival/departure.

[erklik]

> Where is the data sourced from?

https://opendata.transport.nsw.gov.au/dataset/public-transpo...