The incident took place on Shirley Avenue Milton just after 5pm on Saturday afternoon (17th April 2021).
Officers from Hampshire Roads Policing have taken the lead in the investigation that is understood to be fatal in which man has died.
Specialist collision scene investigators have also been called to the incident. They are carrying out measurements and checking road surfaces following the single-vehicle collision involving a dark coloured Chrysler voyager.
A number of road closures and cordons have been put in place to assist with the Police investigation that has been launched
Despite the efforts of paramedics from South Central Ambulance and Air medics, the person died at the scene.