Local firefighters launched an urgent search to reunite her with her owner, who had been taken to hospital.
She was found near the Rattery exit on the Exeter-bound side of the A38 at about 9.45pm.
Craig Timblin, who was involved in the search, said: "She was found after a search of the area of the collision.
"Family members and ourselves were sat in a location where we could monitor areas.
"As we discussed the next moves and a car was opened, Poppy was noticed to be walking up the hill from an area that was on the embankment of the A38 next to the collision scene.
"She took a few seconds to recognise family owners and then made her way to the arms of one of them.
"She was uninjured but dirty and she had lost her collar."
Buckfastleigh Fire Station said: “Poppy is a beautiful poodle-cross who along with her owner was involved in a road traffic collision on the A38 on Tuesday afternoon at Dean Prior.
“Poppy was obviously scared and ran from the vehicle in the direction of Rattery.
“Poppy’s owner was taken to the hospital for checks and we would dearly love to locate Poppy and reunite them after their very scary ordeal."