Emergency services were unable to find anything when they were called out to reports that a cement mixer had careered off the A41 and smashed into trees.
The Herts Air Ambulance was sent to the driver’s aid because the crash was believed to be serious.
But Gary Sanderson from the East of England Ambulance Service said: “The air ambulance went up and down the A41 and landed but they didn’t find anything. “There is some damage to trees but no cement mixer. I don’t know where it has come from.”
Emergency services were called just before 4pm.