More than 60 women across Saudi Arabia have driven cars in defiance of a ban which keeps them from getting behind the wheel.
The women met little protest from police in their push for less restrictions on women in the kingdom.
The campaign's message is that driving should be a woman's choice.
The struggle is rooted in the kingdom's hard-line interpretation of Islam known as Wahabbism, with critics warning that women driving could unravel the very fabric of Saudi society.
Though no laws ban women from driving in Saudi Arabia, authorities do not issue them with licences. Women who drove on Saturday had drivers' licences from abroad, according to activists.
Aziza Youssef, a professor at King Saud University, said protest organisers received 13 videos and about 50 phone messages from women showing or claiming they had driven.
May Al Sawyan, a 32-year-old mother of two and an economic researcher, told reporters she drove from her home in Riyadh to the grocery store and back. Activists uploaded a four-minute video of her driving to the campaign's YouTube account.
Ms Al Sawyan said she was prepared to be jailed if caught by authorities. She said she was far enough from a police car that she was not spotted.
"I just took a small loop," she said. "I didn't drive for a long way, but it was fine."
Ms Al Sawyan's husband and family waited at home and called her nervously when she arrived at the store to check on her, she said. She drove with a local female television reporter in the car. They were both without male relatives in the vehicle, which in itself defies the country's strict norms requiring women to have a male relative in public.
"I am very happy and proud that there was no reaction against me," Ms Al Sawyan said.
It is not clear if police turned a blind eye to women driving or simply did not see the scattered, quick spins around towns. One journalist in Riyadh said there were no roadblocks or checkpoints set up to watch for female drivers. He saw only a few law enforcement vehicles on the road.
A security official said authorities did not arrest or fine any female drivers on Saturday.
Ahead of the protest, authorities offered mixed messages, perhaps cautious not to push too hard against the kingdom's religious establishment. Hard-line clerics say women driving will lead to "licentiousness". A prominent cleric also caused a stir when he said that medical studies showed that driving a car can harm a woman's ovaries.
The ministry that oversees the police warned that violators who "disturb public peace" would be dealt with forcefully. The statement catered to conservatives who saw this as directed at women drivers, but was also interpreted by reformers to be directed at anyone who harasses women drivers.
"This is part of the politics," said Professor Youssef. "My analysis is that government is doing all this to protect ladies from the harassers."
The response to the campaign is in stark contrast the kingdom's first major driving protest in 1990, which saw 50 women arrested. They ultimately had their passports confiscated and lost their jobs.
In June 2011, about 40 women got behind the wheel in several cities in a protest sparked when a woman was arrested after posting a video of herself driving. Later another woman driver was arrested and sentenced to 10 lashes, but the king overturned the sentence.
King Abdullah has gradually introduced reforms since then. The moves, which include allowing women to sit on the national advisory council and permitting women to vote and run in municipal elections, may have readied the deeply conservative nation for change.
But the stringent male guardian system has been left untouched. It requires women to obtain permission from a male relative to travel, get married, enrol in higher education or undergo surgery in some cases.
Women who complain about not having male relatives to drive them places or money to spend on a driver are told by many Saudi clerics to call for better public transportation systems, not a driver's licence.
Despite the obstacles, Professor Youssef said only one woman reported being pulled over by police on Saturday. The woman was asked to sign a statement promising not to drive again and her husband took over the steering wheel, she said.
"We will continue driving and posting videos," she said. "The whole thing is raising awareness and making people get used to us driving as normal."