Police spokesman Richard French says Dakota Culkin was struck Tuesday night after she stepped into the street. She died a day later at a Los Angeles hospital after suffering massive head injuries.
French says there is no active criminal investigation.
Police say the driver stopped and tried to help the 29-year-old. Officers determined the motorist wasn't driving drunk and followed all laws.
Macaulay Culkin's spokeswoman, Michelle Bega, said it was a "terrible tragic accident" and the family had no further comment.
The 28-year-old actor starred in the "Home Alone" films.