Speed cameras are will be used from spring on the M4 in Wiltshire.
The cameras, operated by the Wiltshire and Swindon Safety Camera Partnership, are aimed at enforcing the 70mph national speed limit.
The locations of the cameras will be revealed at a meeting attended by MP Julia Drown on 13 April.
A spokesman for the camera partnership said: "This was approved by the Department of Transport as the areas targeted have a history of casualties."
The scheme will run until the casualty numbers come down.