A £40,000 speed camera was destroyed after it was blasted with a home-made bomb.
Five cameras on the same stretch of the A37 between Bath and Wells in Somerset have been damaged or sabotaged in the past nine months.
Since last May, 12 of the 50 cameras put in place by Avon and Somerset Safety Camera Partnership have been targeted by vandals.
The latest attack took place in the early hours of Sunday morning.
The camera in the village of Emborough, near Shepton Mallet has already been replaced.
One of the other cameras on the road was demolished using an angle grinder and three others were burned using tyres filled with petrol.
'Safety at risk'
The partnership says, across its area covering Bristol, Somerset and Gloucestershire, 12 of its cameras have been destroyed since May.
David Gollicker, partnership spokesman, said: "This incident is quite
different to the other attacks with regard to the amount of vandalism involved.
"It is down to a group of motorists who are actively targeting these fixed
cameras," he said.
Mr Gollicker added that destroying the cameras could create more of a hazard.
"They are a minority group and they must be aware that what they are
doing is putting people's safety at risk."
Avon and Somerset Police added the camera was blown up with easily obtainable homemade items.