A series of average-speed cameras have been installed on a section of the A64 in North Yorkshire ahead of work by Highways England to replace the central reservation barriers.
The cameras will track the speed of drivers travelling between Bramham and Tadcaster Bar, with anyone travelling at more than 40mph on average being issued with a ticket.
They had not been activated yesterday but are due to be operational throughout the works, which are scheduled to last between two and three months.
Read more: More safety camera vans head out on North Yorkshire's roads as police seek to cut fatalities
A Highways England spokeswoman said the speed restriction and cameras were being introduced for safety reasons while the improvement work is carried out.
The work between Bramham and Tadcaster Bar represents the first phase of the scheme, with a second due to follow on the section between Bramham Bar and Askham Bar.
The spokeswoman said the cameras were temporary features and not connected to an ongoing feasibility study into the potential benefits of introducing fixed speed cameras on the road.
It follows concerns about the number of collisions on the route, with 16 fatal crashes and 89 serious crashes in the past five years.
There are currently no fixed cameras on North Yorkshire’s road network and police instead use a fleet of safety camera vans.
The 12 vans not only detect speeding drivers, but can also identify seatbelt offences and drivers using mobile phones.