The lorry, driven by Mr Teo Kian Chwee, 35, overturned a few times and landed on its roof infront of the car on the sliproad.

The impact also caused Mr Pang's car to surge forward and hit the left railings of the expressway.

Mr Teo was trapped in the driver's cabin and had to be extricated by civil defence personnel.

He died of multiple injuries on the spot.

A toxicology report showed that his blood alcohol content was 183mg ethanol per 100ml of breath - more than twice the legal limit. His urine sample contained drugs such as codeine and morphine.

A consultant forensic pathologist said in his report that the level of ethanol in Mr Teo's body would be associated with signs of obvious drunkenness - unsteadiness, incoordination, slurred speech and a staggered gait.

At a coroner's inquiry into Mr Teo's death on Thursday, Mr Pang, 47, was named the potential defendant.

He elected to remain silent.

Station Inspector Raimi Mohd Yusof from the Traffic Police Division said in his investigation report that Mr Pang was driving on the second of the four-lane expressway towards Pan-Island Expressway (PIE) at about 10.35pm that day .

When Mr Pang reached near the end of BKE, the four-lane was split into a two-lane sliproad leading to PIE (Changi Airport) on the left and PIE (Jurong) on the right.

He had intended to take his mother, who was one of the passengers, home to Toa Payoh but ended up at the sliproad leading to Jurong.

Station Insp Raimi said Mr Pang then stopped his car on the left road shoulder and started reversing. By doing this, he had contravened traffic rules, he added.

Suddenly a lorry came from behind and rammed into the rear right of the car.

In his findings, State Coroner Victor Yeo said it was fortunate that the car passengers, including Mr Pang's 85-year-old mother, did not suffer any serious injuries.

'Without the benefit of Mr Pang's evidence, this court is unable to conclusively conclude in what manner the potential defendant had reversed his car, such as the speed of the car just prior to the accident,' he said.

In returning an open verdict on Mr Teo's death, the coroner also said he could not conclude that his death was due solely to the criminal negligence of Mr Pang.

But he had a timely reminder for road users - motorists should comply with the traffic rules and regulations and 'refrain from drink driving at all times.'