Saudi women are to be allowed to drive from midnight local time (21:00 GMT) after a ban comes to an end.
The change was announced last September and Saudi Arabia issued the first
It was the only country left in the world where women could not drive and families had to hire private chauffeurs for female relatives.
At least eight women's rights activists are being detained and could face trial in a counter-terrorism court and long prison sentences for their activism, human rights group Amnesty says.
They include Loujain al-Hathloul, a well-known figure in the campaign for women's driving rights.
Amnesty has also called for wider reforms in Saudi Arabia, where women remain subject to male guardianship laws.
Human rights groups in the kingdom have campaigned for years to allow women to drive.
Dozens of women were arrested for driving in Riyadh in 1990 and some Saudi women began posting videos of themselves at the wheel in 2008 and between 2011 and 2014.
On 5 June, 10 women became the first female
The Saudi authorities have said they expect about 2,000 women to have received