Vehicles headed to Howrah across Vidyasagar Setu were stuck for more than an hour on Friday nightwhen a truck headed to Calcutta ploughed through the bridge’s median and rammed into a lorry on the opposite flank.

Two vehicles collided with the lorry on the Howrah-bound flank that was hit by the truck.

Altogether four goods vehicles were impacted in the accident that took place around 11.45pm on Friday.

The driver of the truck, which swerved and changed flanks, died in the impact of the series of collisions. Police said they had yet to identify the man who appeared to be around 50.

Drivers of three other vehicles — Manirul Islam, 25, Mainur Seikh, 20, and Dipak Das 39 — were seriously injured in the collisions.

The impact of the collisions was so intense that the 12-wheeled truck, loaded with cement, was reduced to a mangled mass. Till late Saturday afternoon, it remained stationed on one of the bridge’s flanks.

The driver’s cabin and the front wheels were gone and the chassis was twisted. The police managed to remove other vehicles from the accident spot.

“The truck driver succumbed to injuries at SSKM Hospital. It isn’t clear why he swerved suddenly and hit the median driver to land on the Howrah-bound flank of the bridge,” said a senior police officer.

“We have found out the details of the truck’s owner from the records available with us and have asked him to turn up.”

CCTV footage revealed the accident took place at a spot adjacent to the office of the Hooghly River Bridge Commissioners, which maintains the six-lane cable-stayed structure.

The police said the lorry on the Howrah-bound flank was hit so hard that it was displaced from the lane it was travelling on and collided with two other goods vehicles — a truck and a goods pick-up van — on the adjoining two flanks.

“The driver of the pick-up van hailed from Baruipur in South-24 Parganas while the two other truck drivers are residents of Chandaneswar in the same district,” the officer said.

Senior officers admitted if the cement-loaded truck had ploughed into a car or a smaller vehicle instead of the lorry, the death toll would have been higher.

Immediately after the accident, senior officers from Hastings police stations and sergeants from Vidyasagar traffic guard reached the spotand cleared the Howrah-bound flanks on the bridge to ensure vehicles moved after remaining stuck following the accident.

Heavy trucks have been frequently involved in crashes on the bridge.