A driver called 999 after a passenger in a passing car leant out the window and pointed what looked like a gun towards him on the A57.
It happened at around 9pm on Friday, July 16.
Armed police were dispatched as it was unclear whether the gun was real or not.
The suspect vehicle was located and searched before a plastic toy handgun was seized by officers.
The three occupants, aged 24, 26 and 31, were arrested on suspicion of possession of a firearm with intent to cause fear of violence.
The 24-year-old has been bailed pending further investigation.
The two other men were released without charge.
nspector Chris Pearson, of Nottinghamshire Police, said: “This would have been a very frightening experience for the victim.
“Although it turned out to be a toy handgun, it would certainly have looked like a real one. Imitation firearms can be indistinguishable to live firearms and we will always take them very seriously when we find them.”