A bus tumbled into a ditch killing two at Naogaon while two others died in separate accidents in Sirajganj on Saturday morning.
Porsha police OC Shaheen Kamal said the accident took place at the Naogaon-Porsha highway's Doyahar intersection around 10am.
The victims have been identified as Seratul Islam, 20, and Tariqul Islam, 30.
The OC said the bus lost control and fell into a roadside ditch killing two on the spot while leaving 10 others injured.
The injured were admitted to Porsha Upazila Health Centre.
Meanwhile, in Narayanganj, a man died after being hit by a car at the Kadda intersection while another pedestrian was run over by a truck at Raiganj, said police.
The latter was identified as Monayem Khan, 45, but the other remained unidentified.
Bangabandhu Bridge (west) OC ATM Aminul Islam said a private car and auto-rickshaw collided at the bridge's west junction highway. After the crash the vehicles hit an unidentified man leaving him dead.
Four auto-rickshaw passengers were also injured.
The injured were sent to Sirajganj Sadar Hospital.
Raiganj Police OC Rashedul Islam said Monayem was run over by a speeding truck and died on the spot.