The 33-year-old was abducted for a short time after his captors stopped his silver VW Caddy van on the Shieldhill to Slamannan road near Falkirk.
It is understood he was restrained and suffered facial injuries in the incident, which happened between 10 and 11pm on January 24.
The victim broke free and flagged down a passing car with a middle-aged couple in the front and two other younger passengers in the back.
The car is described as possibly being a four-door saloon.
Police Scotland are keen to speak to those who were in the car, and to anyone who may have seen a white 4X4 vehicle that was parked on the road between 4pm and 10pm that day.
Detective Inspector Kevin Carr, who is leading the investigation, said: "I am appealing for the occupants of the car to come forward. They stopped for a distressed man on a stretch of road between Shieldhill and Slamannan, and drove him to safety in Shieldhill.
"While this is being treated as an abduction, it was an isolated incident and specifically directed at the victim and at no time was there any danger to anyone else.
"We remain keen to speak to anyone who may have seen the victim's silver VW Caddy van, which was in the Shieldhill area as well as the Baillieston area of Glasgow that evening."
"We would also like to speak to anyone who was on the Shieldhill to Slamannan road between 4pm and 10pm on Friday who may have seen a white-coloured 4X4 vehicle that was parked up."
Anyone with any information should contact police on 101 or through Crimestoppers on 0800 555 111.