HAVERFORD TOWNSHIP, Pa. (CBS) – An elderly driver accidentally struck his wife and daughter Monday morning in Delaware County, according to police.

The incident happened at about 9:30 a.m. in the 500 block of Harrington Road in the Manoa section of Haverford Township. Police say the 89-year-old man was backing out of his driveway and stopped the vehicle halfway down with the transmission still in reverse.

According to authorities, the driver’s daughter, 62, was trying to help her 85-year-old mother get into the passenger seat of the vehicle when unexpectedly, the driver stepped on the accelerator pedal, causing the vehicle to travel backward. Both women were knocked to the ground and sustained serious injuries.

The daughter was flown to the Hospital of the University of Pennsylvania with serious injuries to the head and chest and her mother was taken to the same hospital with injuries to her lower torso.

Haverford Township Police continue to investigate this case.