Some include Western volunteers as well as local truck drivers.
Close to 40,000 people recently have fled from ISIS's last bastion in the Euphrates Valley.
They are driven about 6 hours north to the al-Hol displacement camp under the protection of the Syrian Democratic Forces (SDF).
They get 75,000 Syrian pounds ($150) for each two-day, 600-kilometer round trip.
"We leave for the Omar base in the evening, with trucks in front and behind, and we go together as a convoy. When we arrive at the al-Hol camp, they get off trucks and enter the camp. If there are injured, doctors treat them," explained driver Farhan al-Ali.
Some truckers rely on stimulants to stay awake.
"I take a pill and I can stay awake for 24 hours straight [to drive]," said another driver, Ibrahim.
The United Nations has called on authorities to provide more suitable transportation like buses.
The SDF said on Saturday it will soon make an announcement regarding good news about ISIS.
The extremist group is cornered into a half square-kilometer area.
Reporting by Maya Gebeily | AFP
