The Kessock Bridge, which carries the A9 across the Beauly Firth at Inverness, will be up-graded over a four-month period with the works prompting the area's biggest traffic management upheaval in living memory.
More than 30,000 vehicles a day use the bridge with 11% of these HGV lorries. It carries all those who commute in and out of Inverness from the Black Isle, Easter Ross and beyond as well as being the main A9 artery to the north.
Final preparations are being made for the works, first announced more than three years ago, which are due to start on February 11.
Until June, the north-bound carriageway will be closed to traffic as the urgent need for resurfacing and steelwork defects is addressed.
Transport Scotland has warned motorists they face delays of up to an hour, with drivers asked to consider alternatives to car travel.
In a bid to ease congestion, Conon Bridge station is reopening a week today – 53 years after it closed – to ease the journey for those living in Ross-shire.
ScotRail is also due to increase capacity on its services to the Highland capital.
A plan to introduce a passenger ferry to the Black Isle on the route the Kessock Ferry plied before the bridge was opened in 1982 was mooted but rejected.
As repairs get under way, a dedicated lane will be in place on the bridge for buses, HGVs and emergency vehicles from Tore in the middle of the Black Isle. Stagecoach said it will also put on more buses on services to Inverness.
Once the £18m programme is completed, Transport Scotland claims drivers will see the time of the final part of their journey into Inverness halved.
Cameron Gair, Transport Scotland's bridge assets manager, said: "The Kessock Bridge is a vital artery for Inverness and the Highlands and these works will leave important legacy benefits for the community.
"A modern, refurbished bridge, improved cycle ways and, crucially, vastly improved journey times for motorists once the works are complete.
"With just over a week until this project begins, it is encouraging to see the community pulling together to ensure Inverness remains open for business.
"We have heard examples of employers offering flexible working to staff, local maternity clinics set up so pregnant women don't have to travel into Inverness and individuals planning to take the train or car-share to reduce the number of cars on the road.
"Yes, there will be disruption but we are confident our investment in road improvements and in enhanced public transport means commuters have viable alternatives to sitting in traffic queues during these vital repairs."
The Highland Council leader Drew Hendry said: "We welcome the major investment being made by the Scottish Government in maintaining the Kessock Bridge, which is a symbol of progress in the Highlands.
"We have known about the resurfacing for some time and this has helped us to prepare and offer measures to ease the impact of the closure of two lanes of carriageway.
"As the biggest employer in the Highlands with 900 staff crossing the bridge daily en route to work, we can play an important role in relieving pressure on the bridge, especially at peak times."