0259 GMT January 18, 2020
At least 30 other passengers were injured in the accident early Wednesday, which took place on a major road linking the southern cities of Shiraz and Kerman. It happened around 1:30 a.m., IRNA reported.
At least 14 of those killed were conscripts of the Army's Ground Force.
Police said fatigue or sleeplessness of the driver caused the mishap.
The injured were taken to local hospitals. An hour later, a bus flipped over on a road, also near Shiraz, injuring 47 people.
Iran has one of the world's worst traffic safety records, with more than 400,000 accidents and nearly 18,000 deaths on its roads every year.
The high death toll is blamed on unsafe vehicles and widespread disregard of traffic laws.