Three people were killed and five others injured when a truck hit two human haulers on Rngpur-Dinajpur highway at Paglapir in Sadar upazila on Sunday.   Two of the deceased were identified as Morzina Begum, 24 and Ripon Chandra Roy, 25, of Nilphamari district while the identity of another could not be known immediately.   The truck hit the two human haulers as its driver lost control over the steering around 7 am, leaving three people dead on the spot and five others injured, said Sajedul Islam, officer-in-charge of Sadar Police station.   The injured were taken to Rangpur Mediccal College Hospital