An elderly man was killed in a collision with a heavy goods vehicle in Spackman Lane, Corsham, at 5.07pm yesterday (Monday).
Two PCSOs were quickly at the scene performing CPR on the pedestrian with medical crews arriving at 5.10pm.
A Great Western Ambulance spokesperson said: "Unfortuntalely it was quite apparent when we arrived at the scene that the patient was suffering from injuries incompatible with life and he was pronounced dead at the scene."
Police closed the road when they arrived at the scene and it reopened again at around 10pm.
They are currently investigating the incident and are appealing for witnesses to come forward.
Great Western Ambulance have also advised pedestrians to ensure they are wearing high-visibility clothing when out walking at night.
Any witnesses can contact Wiltshire Police on 101.