SINGAPORE - It was a smashing end to 2018 for Mr Nicholas Sim, and not in a good way.

A large rock smashed through the windscreen of the car he and his pregnant wife were in on Monday afternoon (Dec 31), ricocheting off the steering wheel and narrowly missing the pair.

They escaped with only superficial cuts which they treated themselves.

He later sent footage of the incident to citizen journalism website Stomp.

Mr Sim, 34, who is self-employed, told The Straits Times on Thursday that the incident occurred along the Bukit Timah Expressway (BKE) towards Woodlands.

It was around 2.30pm, and the pair were on their way home to enjoy a relaxing New Year's Eve. Mr Sim was driving and his wife, who is 30 and six months pregnant, was in the front passenger's seat as their car neared a flyover.

Suddenly, there was a loud crash. Dust and glass flew everywhere, and his wife cried out in shock.

"I couldn't see properly, the whole car was cloudy," Mr Sim recalled. "I thought my engine exploded."

The couple were in shock and had no idea what happened. Both their faces and eyes were stinging from the "cloud" in the car, which Mr Sim said was a combination of fine glass and dust particles.

"All I could think of was to get to safety," he said.

Mr Sim quickly pulled over to the side of the road. Fortunately, both of them were not seriously injured.

It was only after a tow truck took their car to a carpark that Mr Sim noticed a large rock in the back seat - next to his groceries, which were somehow undamaged as well.

Describing the rock as "heavy, sharp and looking like a piece of concrete", he said the pair realised afterwards that they were "lucky to be alive".

It turned out that the rock hit Mr Sim's steering wheel hard enough to dent it, and ricocheted to the back of the car. He did not know where the rock came from, only that it had flown straight at the car's windscreen.

"We feel very blessed and protected," he said. "We thank God the rock didn't ricochet off the steering wheel and hit my wife's face, my face, or her belly."

There were many different ways things could have gone south, he added.

"Imagine if there was a passenger in the back seat, if it was a motorcyclist instead of us, or if my hand had been on the part of the steering wheel the rock hit. It would have been crushed."

"If the steering wheel hadn't been in that exact position, the rock would have hit my chest... it could've just ended there and then," he said, adding that there were still glass shards in his shirt when he got home.

Mr Sim said he e-mailed the Land Transport Authority and the Ministry of Transport about the incident, but chose not to make a police report as he had no idea where the rock came from or what the authorities could do about it.

His car was also sent to the workshop for repairs.

Though the incident did not put Mr Sim off driving, it did put him and his wife in a pensive mood.

"We're still trying to wrap our heads around the situation," he said.

As for the rock? "It's still in the car in the workshop," he said.

"We might just hold on to it and reflect."