Two sisters were struck and critically injured as they were crossing a street with their grandmother in Glassell Park Friday night.
One had to have brain surgery due to her injuries.
The 64-year-old man driving the car that hit them has been arrested on the suspicion of driving under the influence of alcohol or drugs.
The collision was reported at 7:30 p.m. at 2640 N. San Fernando Road, near the Glendale (2) Freeway, said Erik Scott of the Los Angeles Fire Department.
Super King Market and Los Feliz Charter School for the Arts are also nearby.
The children, 12 and 6 years old, were taken to a trauma center in critical condition, said Sgt. Steve Bailey of the Los Angeles Police Department's Central Traffic Division.
The younger child was undergoing brain surgery after suffering severe head trauma, Bailey said.
The 12-year-old was in critical but stable condition, Bailey said.
The girls' grandmother was not struck, but was taken to a hospital to be examined, Bailey said.
The three were crossing San Fernando in a crosswalk at Hallett Avenue when the girls were hit, Bailey said.
Witnesses said the car was headed westbound on San Fernando Road around 50 m.p.h. in a zone posted at 35 or 40, Bailey said.