Employees of industrial transport company Jin Quan Engineering (JQE) were arrested for causing damage to an overhead pedestrian bridge along Balestier Road on Friday night.
The Sunday Times understands that driver Noor Khalam Aman, 57, and his supervisor Ng Boon Tong, 59, both Singaporeans, were arrested for causing a heavy vehicle to collide with the overhead bridge. Mr Khalam's driving licence was also suspended and police investigations are ongoing.
On Friday at about 9.30pm, the arm of an excavator being ferried on a JQE trailer hit a pedestrian bridge near McNair Road, damaging it. The excavator belongs to engineering firm Koh Kock Leong Enterprise (KKL).
No one was injured, but the accident resulted in a massive jam, a nine-hour road closure, and overnight works to remove the bridge that had become structurally unsound.
In a statement yesterday, the Land Transport Authority (LTA) said the bridge was "likely" to have been damaged by the excavator, which was not fully retracted while being transported.
The Building and Construction Authority also said its engineers found that the impact of the collision caused one end of the bridge beam to be dislodged from the central support, and recommended that the entire bridge be removed immediately.
The crash also caused part of the railings on the pedestrian walkway to be dislodged. Debris was strewn all over the road when ST visited the scene about an hour after the incident. At about 5.30am on Saturday, the overhead bridge was being dismantled.
When approached, one of the JQE bosses, who gave her name only as Madam Lim, 50, said she did not know what caused the accident and declined to reveal details about the investigation.
KKL's assistant administrative manager, Miss Katie Chai, 35, told ST over the phone: "We aren't sure what went wrong and were quite shocked it happened. JQE is one of the companies we contracted to transport our vehicles.
"We don't have an estimation of the damage costs, but we've contacted our insurance brokers and will see how we can sort this out."
February 2016: A 56-year-old lorry crane driver is arrested after the lifting arm of his lorry scrapes the bottom of the overhead bridge linking Marina Square and Millenia Walk, causing cladding panels to fall.
July 2015: A lorry carrying an excavator hits the bridge linking Thomson Plaza and Bright Hill Drive in Upper Thomson Road, sending debris falling.
October 2011: The retractable crane boom on a lorry hits a 4.5m-high bridge along the Pan-Island Expressway, after the Paya Lebar exit. A part of the boom lands on a car, with a family of three in it. They are taken to hospital. The driver is jailed for a week and banned from driving for nine months.
July 2010: A lorry carrying a crane crashes into a bridge near Sixth Avenue, punching a hole in the walkway. A woman in her 50s on the bridge is injured.
November 1997: A rubbish truck, with the driver trapped inside, dangles for 15 minutes from an overhead bridge in Clementi Road. The driver hit the bridge near Ngee Ann Polytechnic with the crane of his vehicle.
It is not clear if the overall height of the trailer and excavator would have been less than 4.5m had the excavator been fully retracted.
According to law, it is an offence to drive a heavy vehicle with an overall height that exceeds 4.5m without a police escort.
Unless specifically stated, all overhead road structures, such as pedestrian overhead bridges and gantry signs, have a clearance height of 4.5m.
The Sunday Times understands that JQE did not hire a police escort.
Since 2013, there have been 20 cases of overheight vehicles hitting overhead structures, LTA said last year.
Friday's incident is the first reported case since 2010 when LTA had to remove horizontal beams of a pedestrian bridge due to damage from a vehicle.
•Additional reporting by Jose Hong