Commuters are giving themselves more buffer time when planning MRT train journeys to cater for unexpected delays or disruptions.
And when they have important appointments, they would avoid taking the train, a recent public survey on MRT reliability has shown.
The survey, commissioned by The Straits Times, was conducted between Nov 30 and Dec 4 by Moovit, a public transport app and mapping provider.
The online poll of 711 commuters found that 30 per cent factored in up to 10 minutes more for their MRT trips; close to 20 per cent gave themselves 10 to 20 minutes more, while another 14 per cent set aside more than half an hour extra.
Commuters apparently had more confidence in the MRT's punctuality in the past, judging from the poll - fewer respondents factored in additional time, when asked about their experience three years ago.
More than half, or 57 per cent, said they did not cater for any buffer time at all when using the MRT three years ago. In comparison, a quarter of the respondents said they did so now.
Ms Alina Chua, 23, a university graduate looking for a job, takes the East-West Line daily and said travel times have been "irregular". She estimated that out of 10 trips, three of them were longer by 10 to 15 minutes. "If I have a job interview, I will leave home as much as 30 minutes earlier," she said.
About 40 per cent of commuters surveyed said they would avoid taking the train if they had a job interview. Close to 54 per cent would use another mode of transport if they had to be at an important event that required them to be on time.
Singapore University of Social Sciences economist Walter Theseira said the results showed that public confidence in the on-time reliability of public transport had dropped.
He said that if commuters really did factor in more travel time, this would also affect efficiency, as time was wasted on commuting and then arriving early at a destination.
"One of the competitive advantages we have in Singapore over much of the region is... that our transport network is very reliable."
Official statistics, however, paint a different picture of reliability.
They show MRT trains travelled an average of 425,000km this year before encountering a delay of longer than five minutes, far more than the 133,000km in 2015.
Dr Theseira said this is because the authorities excluded faults due to the upgrading of the signalling system on the North-South Line and East-West Lines. It is a one-off project and not reflective of general maintenance and reliability.
But commuters cannot be expected to compartmentalise, Dr Theseira said, and, regardless of the type of fault, they hold the Government and operators responsible.
"Cognitive research shows that salient personal experiences, such as being inconvenienced by a train fault, are much more easily recalled than abstract statistics," he added.
Asked if the MRT tunnel flooding in October and the train collision last month could have dented confidence, Dr Theseira said these incidents could be contributory factors as they were easily recalled events.
In the Moovit survey, commuters were divided on whether train reliability would improve in the next few years. About 35 per cent said they did not know what to expect, while 33 per cent expressed confidence that MRT reliability would improve. The remaining 32 per cent were sceptical.
Retired sales promoter Marvin Goh, 63, said not all MRT lines were unreliable. He praised the North-East Line for being "efficient".
And, despite occasional frustrations with the MRT, Ms Chua said: "Look at other cities such as Bangkok and Kuala Lumpur. Our MRT system is way better."