SINGAPORE - A part-time Grab driver who drove under the influence of sleep-inducing drugs hit a cyclist without knowing he had done so.

Muhammad Fadzuli Mahmood, a lifting technician by day, took on the driving job to earn more money.

On Oct 25, 2016, he took some cough syrup to induce sleep before he started his shift at midnight. He drove for a few hours before returning home as he was tired and sleepy.

At 5.30am, he went out again despite still feeling very tired and sleepy. He took two epam tablets - which are actually used for insomnia - that he had bought in Lorong 12 Geylang to give him "energy to work for long hours''.

On Wednesday (Jan 3), the 40-year-old was jailed for 15 months and banned from driving for eight years for causing the death of a foreign worker along Bartley Road East by committing a rash act. He also admitted to driving under the influence of drugs to such an extent as to be incapable of having proper control of the car.

Deputy Public Prosecutor Teo Lu Jia told the court on Tuesday (Jan 2) that Fadzuli was driving very unsteadily along Hougang Avenue 3 when he swerved along the road repeatedly.

When he entered the slip road into Bartley Road East, he was still feeling drowsy, tired and sleepy. He continued driving in a very unsteady and dangerous manner, swerving along the three-lane road repeatedly, and occasionally, straddling two lanes.

He did not notice that Mr Karunanidhi Arul, a foreign worker from India, was cycling on the road.

As he did not have proper control of his car, it veered to the right and mounted the kerb. Even then, he did not stop or engaged his brake. He continued driving, side-swiping the rail guard in the process. He then collided into the 36-year-old construction worker without realising it.

He continued driving for about 10 seconds before stopping to check on the damage to his rental car. It was only after he got out of his car that he saw Mr Karunanidhi lying unconscious on the grass and bleeding from his head and mouth. Fadzuli called the police.

A toxicology report showed that he had taken six kinds of drugs, including codeine and nitrazepam. His nitrazepam concentration was more than four times the toxic level.

All those drugs were found to have dangerous side-effects such as sedation, sleepiness, disturbance in attention, abnormal coordination, blurred vision, dizziness, disorientation and reduced alertness.

DPP Teo, arguing for at least 15 months' jail and eight years' disqualification to be imposed for the charge of causing death, said Fadzuli's culpability was high.

She said the fact that he had deliberately taken drugs and chosen to drive in his intoxicated state was a serious aggravating factor which greatly exacerbated the gravity of the offence.

Just 10 days before the accident, he had paid a $200 composition fine for inconsiderate driving.

In passing sentence, District Judge Marvin Bay said Fadzuli persisted despite knowing the risk that he posed to other road users.

"In his prolonged erratic drive, it would have been increasingly evident to Mr Fadzuli, even before he entered Bartley Road, that he was losing his ability to exercise proper control of his car,'' he said.

The judge said the aggravating factors included Fadzuli's prolonged, persistent, deliberate bad driving, as well as his self-induced pharmaceutical haze which clearly impaired his judgment.

Fadzuli could have been jailed for up to five years and/or fined for causing death by a rash act. For driving under the influence of drugs, he could have been fined up to $5,000 or jailed for up to six months.