Ever been at a bus stop tracking your bus on a mobile app only to see it disappear rather than arrive?
The developer of real-time travel application TripView thinks he knows what’s happening with these so-called “ghost buses”.
Most transport apps use GPS data to track buses as they travel along their route.
The system relies on both a device in the bus and real-time information from customers tapping on and off with their travel cards.
Regular bus timetable information and a log of when drivers sign on at work also helps determine the location of buses and when they should arrive.
Collectively this data – in NSW – is the Public Transport Information and Priority System.
The PTIPS data – provided by Transport for NSW – is estimated to be 99 per cent accurate for arrival times, a spokeswoman told AAP.
But sometimes things go awry.
If GPS data isn’t available – for whatever reason – some travel apps revert to using old-school timetable information. Hence you may see a bus approaching when it doesn’t actually exist.
It may have been cancelled or the bus itself switched off when the driver takes a break, for example.
Similarly, if travel-card consoles aren’t working. apps may again switch to showing estimated arrival times.
“From a TripView perspective, a bus should only disappear from the map if there is no longer GPS data for that bus on Transport’s real-time data feed,” TripView developer Nick Maher told AAP.
“I sometimes receive reports of this where it turns out that the bus in question wasn’t providing any real-time data. In this case, TripView would have just been showing the scheduled time.”
A Transport for NSW spokeswoman acknowledged some external apps don’t always use PTIPS data.
“At times they may apply their own logic to interpret (PTIPS) data … which can in turn cause inconsistencies in tracking information,” she told AAP.