After a night of drinking, all he wanted was a cheaper ride home at 3.30am, when the other GrabShare passenger, drunk, vomited on him.
The student, who wanted to be known only as Daniel, 20, said this happened two months ago when he took the carpooling ride from Liang Court shopping centre near Clarke Quay.
He told The Straits Times: "The other passenger seemed quite sober, and the driver gave us plastic bags. But halfway through the trip, he vomited on me. Vomit got all over my jeans and shoes.
"The food, alcohol and puke smell was horrible. Windows had to be wound down."
The student threw away his jeans and shoes, which cost $107 and $118 respectively, when he got home 15 minutes later.
Unpleasant experiences like this is a reason why Grab has disabled its GrabShare ride service between 1am and 5am every day. It reportedly informed Grab drivers of the move earlier this month.
In a statement to The Straits Times yesterday, the ride-hailing giant confirmed the move and cited "unruly passengers" as a reason.
The Grab spokesman said: "We have received feedback from our driver-partners and passengers that it can be an unpleasant experience to be matched with unruly passengers on the same GrabShare ride.
"As most of these reported incidents happen between 1am and 5am, disabling GrabShare during this period helps create a safer and better experience for both drivers and passengers."
The spokesman added that drivers and passengers can continue to choose other Grab services during those hours.
Grab driver Gabriel Goh, 44, who usually starts driving after 10pm, said he has encountered incidents of GrabShare passengers behaving rowdily and rudely to others on the same ride.
He said: "Once, a drunk passenger even started harassing the other passenger and I had to make sure that he was not being inappropriate to her, on top of keeping my eyes on the road.
"Such cases inconvenience everyone, and I agree that the service should be removed at those hours, than to wait for an argument or accident to happen in my back seat."
However, Mr Don Chi, 22, a full-time national serviceman, was disappointed that Grab has disabled the ride sharing service during those hours, given that it is between 10 and 30 per cent cheaper.
He said: "I would go out to drink and club, then take GrabShare home around 3am, as I can save about $4."
He added that he took GrabShare rides between 1am and 5am about 20 times in the past year.
"It's more efficient because many people are taking Grab from the same place. Even when there are other drunk passengers, usually it's a quiet ride as they'll be sleeping," he said.
The Grab spokesman added that the firm recently enhanced its in-app emergency button, so that passengers may alert an external security company and their emergency contacts if there is an urgent need for assistance.
The app can also provide auto-alerts to passengers when any unusual travelling pattern is detected.