Seeing that the 21-year-old student had fallen asleep in his car, he kissed her, touched her breasts, slipped his hand down her jeans and panties, and made her touch him.
That car ride home for the victim, which normally takes 20 minutes, wound up taking 90 minutes that morning.
The incident took place on 23 Sept last year.
The victim had boarded the Grabcar after a day of classes, a football game, and a beer-drinking session.
She woke up when she felt Ng leaning against her body and stroking her body.
At the time, the car was just outside her home.
Shocked, she paid him S$20 and left the car, leaving behind her belongings which included a shoe bag and mobile phone in the process.
The victim then told her mother what happened and made a police report.
Ng was today sentenced to 16 months jail for committing outrage of modesty.
He cannot caned as he is above 50 years old.