The projects include diplomatic buildings, procurements for the railway, and highway development
Police said the accident at Shahjadpur Upazila early on Tuesday left a couple and their six-year-old son dead on the spot.
The injured are being treated at local hospitals, he said.
Around 5:30am, a loaded truck lost control on the Dariyapur-Dilruba Road and crashed into the slum beside the road, said the police officer.