A Saudi woman who defied a driving ban in the kingdom was injured and her companion killed when their car overturned in the northern Hael province, a police spokesman said on Monday.
"One woman was immediately killed and her companion who was driving the car was hospitalised after she suffered several injuries" when their four-wheel-drive vehicle overturned late on Saturday, said police spokesman Abdulaziz al-Zunaidi.
Ultra-conservative Saudi Arabia is the only country in the world where women are not allowed to drive.
However, they get behind the wheel in desert regions away from the capital.
There have been several incidents reported in recent years of women being killed in accidents while driving despite the ban, one of a host of restrictions imposed on women in the kingdom.
In November 2010, a Saudi who defied the driving ban was killed along with three of her 10 female passengers when her car overturned in a crash.
A group of activists launched an Internet campaign last year urging Saudi women to defy the ban on driving.
The icon of the campaign, Manal al-Sherif, a 32-year-old computer security consultant, was arrested on May 22 and detained for 10 days after posting on YouTube a video of herself driving her car around the eastern city of Khobar.
Since then, women regularly get behind the wheels of their cars, according to the activists.
Five Saudi women were arrested while driving in late June in Jeddah.
Women in the kingdom who have the means hire drivers while others must depend on the goodwill of male relatives.
They are also obliged to be veiled in public, and cannot travel unless accompanied by their husbands or a close male relative.