Traffic snarls at the Woodlands and Tuas checkpoints stretched for more than a kilometre yesterday as Singaporeans tried to take advantage of the long Good Friday weekend to travel to Malaysia.
At 5pm, the waiting time for cars at the Causeway and the Second Link heading towards Johor was up to two hours long.
Seasoned users of the checkpoints have adjusted their plans to try to avoid the jams.
Media relations executive Janice Tan, 24, who travels to Johor Baru every weekend with her parents to visit relatives and buy groceries, said: "We expected the jam to be worse on Thursday night because of the holiday on Friday.
"People assume there will be a jam on Friday, so they would try to cross over on Thursday night. But we have decided to go on Friday in the morning instead."
Her parents drive to JB at 8am every Saturday, but they have decided to set off an hour earlier today.
"We usually take the Second Link as it's less congested. But if traffic is piling up there, we will head to the Causeway. We also try to monitor the traffic with apps."
Causewayjam.com is one Web application that charts traffic trends at the Causeway and Second Link to help drivers beat the queues.
It was created by Mr Hayden Lak, 35, a permanent resident who runs a tech business here.
Mr Lak, who lives in Johor with his parents and drives into Singapore for work about three times a week, has been commuting across the border for two decades.
"I usually avoid travelling on the eve of a public holiday because the jam is terrible. I also avoid the holiday itself from morning until late afternoon," he said.
He said he had been stuck in a jam for more than two hours before, and knows how agonising it can be.
Using traffic data obtained from Google, the app was launched last month and gives users an estimate of how long they can expect to wait in traffic.
The app also stores this data and plots it on a graph, allowing users to view traffic conditions in, say, the previous three hours. Commuters can use this information to try to work out traffic trends in the following hour.
The app had more than 3,500 visitors yesterday, up from about 2,500 on an average day.
Mr Norman Lai, 35, a permanent resident who lives and works here, travels to JB about twice a week to visit his parents.
The sales executive had originally planned to go back late last night, but said he might postpone his trip if the jam persisted through the holiday.
Ms Nicole Loh, a Malaysian studying at Nanyang Technological University, travels home to JB once a week.
She avoids commuting across the Causeway during peak hours - after 5pm - and said the best time to do so was from 2pm to 3pm.
The Immigration and Checkpoints Authority of Singapore (ICA) said on Monday that traffic flow through the land checkpoints at Woodlands and Tuas is expected to be heavy today. Arrival traffic is expected to be particularly heavy on Sunday.
The ICA added that traffic build-up would be inevitable because of security checks, which remain its top priority to counter potential threats to Singapore.