A motorcyclist allegedly riding without a helmet was hit by a private bus on Friday afternoon when the two-wheeler sped out of a bylane, which converges with Remount Road here, and tried to cross the path of the vehicle.

The motorcyclist, identified as Anil Verma, suffered head injuries and died on the spot. The accident triggered a mob attack on the bus and three other buses that were coming from the opposite direction. One bus was ransacked and the two others were set ablaze.

Witnesses said both the motorcycle and the bus, on route 12C/1A, were moving at a high speed and so were the three buses coming from the opposite direction.

“The collision took place when the biker, with two riding pillion, zoomed out of the bylane. While the bus driver failed to brake, the motorcyclist could not control the speed. All three (on the motorcycle) fell on the road and one of the them came under the wheels of the bus. The remaining two suffered minor injuries,” said a witness, who was sitting at a tea stall near the spot.

Another witness said the three buses that were torched by the mob had no connection with the accident.

People threw stones and concrete chunks at the buses and smashed their windscreens with rods.

The driver of the offending bus — that plies between Joka and Howrah — fled from the spot. Three fire tenders doused the flames.

Verma, 32, a resident of EJC Dock, Junction Road, drove a trailer for livelihood. His wife and three children live in their ancestral home in Bihar.

“I have informed my sister. They are coming to Calcutta,” said Verma’s brother-in-law, who lives in the same locality.

Remount Road and the connecting thoroughfares in the Kidderpore dock area are traditionally carriers of heavy vehicles and often witness reckless driving, police officers said.

The stretch is a two-way road without a central line dividing the two opposite flanks.

“The percentage of traffic violation in the area is very high. Motorcyclists are specially reluctant to wear helmets. We keep on conducting awareness programmes to ensure that they follow the rules for their own safety,” said an officer of the traffic department.