Impact of Bus Arrival Timing System Faults on Bus Services and Commuters, and Corrective Measures Taken

Written Reply to Parliamentary Question 

Ms He Ting Ru asked the Acting Minister for Transport regarding the fault in the bus arrival timing system

a.      how many bus services and commuters were affected;

b.      what post-deployment checks are or have been conducted on the vendor’s system to ensure accuracy; and

c.      whether the reported root cause being a memory cache build-up raised cybersecurity or resilience concerns.

Reply by Acting Minister for Transport Jeffrey Siow: 

1.     Around 4,000 buses were affected by intermittent data transmission and missing bus arrival timing predictions. As buses are deployed across services at different times, we do not have an estimate of the impact on commuters. Bus operations were not impacted otherwise. Predictions from the Expected Time of Arrival system are cross checked against the actual arrival timing of buses logged via the separate Bus Fleet Management System to identify any spikes in inaccurate or missing predictions.

2.     Based on preliminary investigations, the root cause of the incident was defective software coupled with a server failure in January 2026. These resulted in a buildup of data in the internal memory storage of on-board data transmitters, which eventually prevented many of the transmitters from functioning properly. There are no cybersecurity concerns. The software has since been fixed and the same error should not recur. An upgrade of the Bus Fleet Management System has also been in progress since 2024, and will integrate and improve bus arrival time predictions.