The A350 has been closed in both directions after an elderly man was involved in an accident with a car near Melksham Cemetery.
It is believed an 85-year-old man was struck by a small Renault as he walked out of the cemetery shortly after noon.
He has suffered shoulder injuries, but is not thought to be in a serious condition.
The Wiltshire Air Ambulance was called to the scene, but was not required, and the man was taken to the Royal United Hopsital in Bath by road ambulance.
Police officers were called to the scene by paramedics at 12.20pm, and imediately closed the road between the B3107 Countrywide roundabout and the Berryfield roundabout near the A365.
Motorists are advised to avoid the area, with severe traffic congestion already reported.
The A350 was reopened at 2.22pm.