An eight-month programme of major maintenance works have begun on a stretch of the M56 motorway between Runcorn and Hapsford.
Temporary average speed cameras have been installed on the Helsby viaduct section of highway between junction 12 at Clifton and junction 14 Hapsford to protect workers.
Highways England said works began in late March but will pick up the pace with the bulk of the construction to take place after the Easter weekend.
They are due to run until November.
The Cheshire route, which head towards Chester in the west and Manchester to the east, has earned a reputation in recent years for frequent collisions.
However, there is no indication for that being the reason for the project.
A Highways England spokesman said the viaduct has deteriorated over the years and needs "significant essential maintenance repairs" to ensure the structure remains safe in the future.
Concrete repairs are taking place under the viaduct itself, an in addition Highways England pis to conduct the following works on the M56:
- Replace the drainage system.
- Waterproof the deck and replace bridge joints.
- Install a safety barrier along the sides and on the central reservation.
- Carriageway surfacing and replacing the road markings.
Overnight closures will be in place across the both the westbound and eastbound carriageway from May 21.
In the meantime, there will be full closures on the westbound from junction 12 Runcorn to 14 junction each night from Monday, April 20, to Friday, April 24, and on the eastbound carriageway overnight on Tuesday, April 21.
Overnight closures will be in place with a signed diversion to allow a contraflow to be installed to allow for lane closures.
A statement from Highways England said: “Concrete repairs will continue underneath Helsby Viaduct and will be ongoing until the completion date.
“Advance work on the M56 has also started and will finish in time for the Easter period.
“The main construction work on the M56 will start after the Easter Bank Holiday and will be in place until the end of November 2020.
“For safety of road users and our workforce, a contraflow system will be in place.
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“The contraflow will allow us to carry out our work as quickly as possible and keep three lanes open for traffic to minimise disruption and delays.
“A stepped 50mph, 40mph speed limit will also be in place.
“To install the contraflow, overnight closures are required on both carriageways of the M56 between junctions 12 and 14.
“As the work progresses, further overnight closures are needed to adjust the contraflow and working area.”