Four people have died as a result of traffic accidents in Queensland, including two adults and a child travelling in the same car.

Two adults and a child have died after their car collided with another in southwest Queensland.

Police say the cars were travelling in opposite directions when they collided 60km east of Quilpie at about 5pm on Thursday.

A man and infant were pronounced dead at the scene. A woman from the same car died later of her injuries.

Another man, the only person in the other vehicle, sustained non-life-threatening injuries.

Meanwhile, a 63-year-old Glenore Grove man died of injuries he sustained when his light truck veered off the road on the Warrego Highway at Tivoli on October 4, 2013.