A driver threw an aerosol can at another man's car in a fit of road rage.
When the victim, a 29-year-old from Seaford, tried to talk to the road rage driver, he was subjected to unprovoked verbal abuse.
Traffic was queuing west along Drove Road in Newhaven towards the roundabout junction with New Road when the incident happened at 11.10am last Tuesday.
The victim was driving a white Peugeot 208 when a man in a white Audi A3 began honking his horn at him before hurling the aerosol can from his car.
PC James Bunkin said: "The victim suffered unprovoked abuse and had his damaged vehicle because of what appears to be the other driver's impatience.
"I would like to speak to anyone who saw the incident happen or who may have experienced similar incidents with the Audi driver."
Anyone with information should email email@example.com quoting serial 590 of 05/08, call 101 or contact the independent charity Crimestoppers anonymously on 0800 555111.