The bridge that runs over the railway line on the A18 at Melton Ross between Singleton Brich quarry and Humberside Airport is to be repaired.
Repairs are needed following an inspection of the bridge in May 2013 that highlighted a structural weakness within the bridge deck. The bridge deck will be strengthened and new parapets will be erected to stop drivers going onto the railway.
While work is not expected to start until November to repair the bridge, temporary traffic lights are in place now to enable workers to establish the best repair solution.
There is also a one-way traffic system in place over the bridge. The speed limit will also reduce from 60pmh to 30mph.
When work to repair the bridge starts in November, it is excepted to take around three months to complete.
The cost of the work is £750,000.
Coun Nigel Sherwood, cabinet member for Highways and Neighbourhood at North Lincolnshire Council, said: “The inspection highlighted a number of repairs that are needed on the bridge to help keep it in good working order.
“This is a major scheme that will take time to complete and we welcome people’s co-operation.
“The work is essential and we will do all we can to limit disruption, but drivers will need to allow a little more time for their journey while work takes place.”