Claudia Tolu, a Romanian who lived with her Italian husband in Aosta, was hit by a car as she walked along the A26, near the exit for the Piedmont town of Casale Moferrato, at around 5am on Monday morning, La Stampa reported.
The woman had got out of the car she was in after rowing with her husband as they made their way home from dinner in the Turin comune of Poirino.
In a fit of rage, 47-year-old Alfonso Caputo left her on the road and drove off.
The woman walked some 20km along the hard shoulder before being hit on a bend by a driver from Alessandria.
“I couldn't do anything to avoid her,” the 67-year-old motorist, who is now being investigated for involuntary manslaughter, told police.
Her husband, who is also under investigation for complicity to involuntary manslaughter, threatened to kill himself after hearing the news. He is being treated for shock at a hospital in Aosta.