Police closed the motorway yesterday morning to investigate the scene of the crash that killed North Taieri brother and sister Shannon (22) and Danielle (17) Kiriau.
The pair died when the Honda Integra car in which they were passengers went out of control and crashed earlier this month.
Cameron Presland (20) was driving the illegally modified car when he lost control on a slight bend on the Southern Motorway, near Green Island.
A police spokeswoman said the investigation into the crash was ongoing and no charges had yet been laid.