Residents are being warned of a scam in which conmen cold-call households posing as council highway contractors.
Hertfordshire County Council said residents in areas where road works were being carried out were being offered driveway resurfacing at a reduced rate.
Victims were being told the price is lower because of the works already going on.
Terry Douris, Cabinet Member for Highways, said: "Contractors working on behalf of Hertfordshire County Council will never approach members of the public to offer discounted services and we would ask residents to report these doorstep scams to the Citizens Advice Consumer Service on 08454 04 05 06.
"Our advice is to always say no to dealing with anyone who makes a cold call to your home to try to sell goods or services."
Hertfordshire County Council said all its staff and contractors always carry ID and will be happy to show this if asked.