Bus arrival time system to take 4 days to fix completely; issue affecting 50% of public buses: LTA
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A memory cache build-up had disrupted data transmissions between buses and the central servers that compute the estimated arrival times.
ST PHOTO: JASEL POH
Follow topic:
- LTA faces a technical issue disrupting bus arrival time data due to memory cache build-up in bus systems; about half the fleet is affected.
- Engineers are physically clearing the cache on affected buses, a process expected to take four days to complete fully.
- While testing the system, over 60% of bus arrival times will be available from Jan 23, with full restoration gradual; commuters should still expect some inaccuracies.
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SINGAPORE – It will take another four days before a technical issue with the system showing estimated bus arrival times
In a statement on the evening of Jan 22, the authority said that its engineers and system contractor discovered a memory cache build-up in the on-board systems of some buses.
This disrupted data transmissions between buses and the central servers that compute the estimated arrival times, with about half of the bus fleet – across operators – being affected. As at the end of 2024, there were 5,841 public buses in Singapore.
To rectify the issue, LTA said that it is working with the system contractor to reconfigure the system and clear the cache on all the affected buses.
This involves physically servicing the devices on the vehicles and, due to the scale of the work needed, the authority expects it to take about four days to resolve.
In a normal scenario, a cache stores data that is frequently used, so that information can be retrieved more quickly. However, as the cache stores more and more data, it could result in systems behaving more sluggishly and, in some cases, even glitching or crashing.
The Straits Times has asked LTA why the cache was not cleared before the build-up was detected, and if it will introduce measures to do so.
LTA said that it will switch on the system from the start of passenger service on Jan 23 for testing and stabilisation, but bus arrival timings will not be fully available or accurate.
Even so, LTA said that more than 60 per cent of bus arrival timings will be put up. The rest will be restored gradually.
As a result, passengers will still observe missing arrival times or those showing longer bus intervals, but these should gradually become less common as the system is restored progressively, it added.
LTA had initiated a reset of its expected time of arrival system for buses at 8pm on Jan 21, following inaccurate bus timings and long wait times being displayed to commuters.
The wrong information was attributed to an intermittent transmission issue with the on-board systems of some buses, which it earlier said affected a small proportion of buses.
LTA first detected the issue on Jan 10, and said that further inaccuracies were discovered over the course of the week. The technical problem was announced to the public on Jan 21.
Since the reset, bus stop displays and apps such as LTA’s MyTransport.SG, as well as third-party ones, have not been able to provide information on bus timings.
Bus operations continue as scheduled, LTA added.
Commuters are advised to visit the websites of transit ticketing provider SimplyGo or one of the public bus operators to get information about the planned frequencies of bus services.
“We thank commuters for their patience while we work to resolve the issue and apologise for the inconvenience caused,” the authority said.
It added that it would provide an update once the system is restored.
