The traders were returning to their neighbourhood after buying vegetables from the wholesale market in Manikganj’s Jaagir.
The mishap occurred at Lama Upazila’s Yangsa around 7:30am on Thursday, police said.
Lama Police Station OC Sirajul Islam said the truck, which was carrying equipments and workers for installing a mobile tower, was heading towards Lama from Cox’s Bazar’s Chakoria.
The truck overturned on the highway leaving four dead on the spot. The other three died at the Chakoria Upazila Health Complex, said the police officer.