A teenager was pronounced dead at the scene after a collision on a major motorway in Wiltshire on July 18.
The westbound carriageway was closed immediately, while eastbound traffic was halted for two hours to allow air ambulances to land on the central reservation.
Police have opened a serious collision investigation and are urging anyone who witnessed the incident or captured dash‑cam footage to come forward.
Individuals with information are asked to contact the investigation team at 01225 694597, quoting log number 398.
