A new type of speed camera is being used in Cornwall to make motorists pay heed to reduced speed limits through a major road resurfacing project.
The cameras work out a vehicle's average speed
The Highways Agency will start work on the £2.75m scheme on the A30 between Loggans Moor and Hayle at the weekend.
There will be lane restrictions in both directions, with a 40mph (64km/h) limit enforced by new average speed cameras.
They measure the average speed of a vehicle through the whole stretch of roadworks and not at a single point.
The work includes renewing safety barriers and installing new drainage channels, which will affect both carriageways of the A30 at Hayle.
It is the first time this type of speed equipment has been used in Cornwall.
Highways Agency spokesman Peter Heron said the cameras should encourage motorists to drive sensibly.
"There are two sets of cameras - one at each end of the site and they have number plate recognition.
"They recognise a vehicle as it passes through the first camera, then check the time it takes to pass the second camera to work out the average speed.
"If that is above the speed limit it will be passed to the police for enforcement."