Sheffield's famous Tinsley Viaduct is set for a series of road closures to carry out urgent repairs.
A series of 'vital improvements' are set to be carried out to the landmark two deck structure which carries both the M1 and A631 across the Don Valley.
The massive £5.4million renovation programme by Highways England will get under way in August and is set to run into next year - and motorists are being warned of closures and diversions while the repairs take place.
A spokesman said: "Tinsley Viaduct is probably one of the most well-known roads in South Yorkshire.
"Highways England looks after this impressive viaduct and next month a number of vital improvements will be carried out to the barriers, footpaths, drains, and road surface of the lower deck."
The 50-year-old viaduct, the first 2-tier bridge of its kind in the UK back in 1968, will see work carried out in three phases.
Around 2.5 miles of safety barriers will be replaced, the steel structure will be waterproofed, 20,000 square metres of resurfacing will be put down and just over a mile of footpath will be improved.
The work will be carried out in three phases, starting on the northbound carriageway. The majority of traffic will be diverted on to the adjacent service road.
A reduced speed limit of 30mph will be in place.
HGVs will be diverted on to the local road network via Meadowhall Road and Meadowhall Way. For the northbound closure they will also use Blackburn Meadows Way.
Work on phase one of the scheme will start on Monday, 6 August on the northbound carriageway and is expected to last 11 weeks.
In November, phase two of the scheme will start on the service road and traffic will be unaffected.
Once that section has been completed phase three will start on the southbound carriageway with the same traffic arrangements as the northbound closure.
Around nine different contractors will be working on site 24/7 to ensure the work is completed as quickly and safely as possible.
Highways England project manager Russell Mclean said: “Tinsley Viaduct is a unique piece of our road network and that is why we carry out regular inspections and maintenance work to ensure it remains in good working order and continues to provide a vital road link for the community.
“We will be making full use of the road closures by carrying out a range of maintenance and improvement work. This includes replacing the barriers and improving facilities for pedestrians, improving safety along this route.”
Back in 1968 the two tier road bridge cost £6m to build and was constructed using steel box girders - it contains 12,500 tonnes of steel and 81,000 tonnes of concrete and the structure marked its 50th anniversary in March.
The viaduct is one of Sheffield's most prominent landmarks and it and the adjacent cooling towers that were demolished in 2008, even featured in hit comedy film The Full Monty.