Driving on the Pan-Island Expressway (PIE) yesterday morning, he saw a damaged black car in the middle of the four-lane road.
Then he was shocked by the sight of a severed left arm on the road beside the car and a piece of railing piercing the vehicle.
When Mr Muhammad Azhari approached the car, the driver was motionless.
Paramedics later pronounced the man dead at the scene.
Mr Azhari, 32, a businessman, told The New Paper that he was travelling home at about 1.50am yesterday when he came across the vehicle near the Safti Military Institute bridge on the PIE, in the direction of Changi Airport.
After he stopped his car by the side of the expressway, he saw a severed arm near the car.
A piece of the railing, about 5m long, had pierced the car from the front bumper through to the rear - impaling the driver, he said.
He also noticed the left side of the car was badly damaged.
"It was at a right-hand bend. Instead of cornering right, the car must have gone straight and hit the railing, which then pierced through the car," he said.
Mr Azhari said only one other driver had stopped to help. "According to the other car driver, who arrived about a minute before me, all the cars who were ahead of him just drove past," he said.
The police and the Singapore Civil Defence Force (SCDF) said they were alerted to the accident at about 1.50am yesterday.
The SCDF sent two fire engines and an ambulance to the scene, where paramedics pronounced the driver dead.
The New Paper understands the driver was identified as Mr Tan Hock Hai, who was in his 40s.
Mr Azhari was so affected by the accident he posted about it on his Facebook page, as well as the JB Traffic, Road Block & Portholes Report Facebook page, to warn road users to be careful when driving along that stretch.
He wrote: "Please slow down when travelling along PIE towards Changi, at the dangerous bend under the Safti bridge. Especially those travelling on PIE from Tuas Checkpoint."
3 HURT IN CTE CRASH
In another accident yesterday, three people were hurt in a collision between two motorcycles and a car on the Central Expressway (CTE), near Cairnhill Road, at about 8am.
The police said the three victims, aged between 32 and 46, were taken to Tan Tock Seng Hospital.
An SCDF spokesman said two of the injured were a man and a woman in their 30s, while the third victim had minor injuries.
All three are believed to have been on the motorcycles, reported The Straits Times Online.
The accident caused congestion on the expressway all the way to the Ang Mo Kio Avenue 5 exit - about 9km away - according to an update on Twitter by the Land Transport Authority.
The police are investigating both accidents.
This article was first published on November 3, 2016. Get The New Paper for more stories.