A CANBERRA couple on a festive road trip to Adelaide just days before Christmas were killed instantly when their vehicle collided with a prime mover at 100km/h, a coronial investigation has found.

Shanjing Xing and Kai Lun Chok departed their residence in Canberra on December 22, 2023 for a holiday in Adelaide.

At about 5.25pm, Mr Lun Chok was driving, with Ms Xing in the front passenger seat, a...