It happened at the corner of North and Leverett.
According to police, the passenger, Carolyn Caldwell of Springdale, was taken to Washington Regional Medical Center with head-related injuries.
We're told she is in ICU; no word yet on the condition of the driver.
The investigation is still ongoing.
A few other accidents, involving motorcycles, also happened over the weekend in Fayetteville and surrounding areas, according to police.
One on north college resulted in minor injuries and only involved a single motorcycle.
Another happened in a parking lot near Thompson, and police say the driver tried to flee.
And a car versus motorcycle accident happening near Main street and College.