The four, all from Behala area, had gone for a trip to Falta and were returning home when the accident occurred.
The driver, who was missing, probably lost control of the vehicle in fog that descended in the area, the sources said.
The deceased were identified as Hrishikesh Mondal, Anupam Sardar, Avijit Sarkar and Gopal Sardar. All were in the age group of 40-45.
