The crash occurred around 10:30 p.m. on Solomons Island Road at MD Route 665 in Parole.
The woman was walking in the travel lanes when she was struck by a 2006 Toyota Scion heading south on Solomons Island Road attempting to merge onto MD Route 665 East.
She was taken to a nearby hospital for treatment of serious injuries.
The Toyota driver, a 42-year-old Annapolis man, was unharmed and immediately stopped after the crash to call 911.
Heavy rainfall and the woman’s dark clothing may have contributed to the accident, police added.
The investigation is being led by the Anne Arundel County Traffic Safety Section.
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