The victim's identity is being withheld pending notification of her family.
A Toyota 4Runner going south on Harbor Boulevard struck the victim, who was crossing Harbor Boulevard.
The 4Runner, driven by 52-year-old Irvine resident Fern Eisler, was then hit from behind by a Toyota Corolla, driven by 20-year-old Irvine resident Neal Eisler.
Both drivers are participating with police in the investigation.
Anyone who may have witnessed or has information regarding this traffic collision is asked to contact /*Costa Mesa Police Department*/ investigator Rick Cummings at (714) 754-5264.
City News Service contributed to this report.