Four weeks of overnight carriageway closures will take place on Perth’s Friarton Bridge from Monday January 20.
It will enable work to examine the 45-year-old structure which carries the A90 trunk road over the Tay.
Diversions through Perth will be in place during the closures which are set to end on Saturday February 15.
The inspections are being carried out by Amey on behalf of Transport Scotland.
An Amey spokesperson said: “The routine inspections are required to understand the current condition of the bridge.”
Between Monday January 20 and Friday January 31 the northbound carriageway will be closed on weeknights only (Monday to Friday) from 8pm to 6am.
And between Monday February 3 and Friday February 14 the southbound carriageway will be closed on weeknights only (Monday to Friday) from 8pm to 6am.
The following signed diversions through Perth will be in place during the overnight closures.
Northbound closure: Northbound traffic will be diverted via M90 Junction 10 to Broxden Roundabout. Traffic can then take the third exit and follow the A93 Glasgow Road to South Street and on to Queen’s Bridge.
Traffic can then turn right after Queen’s Bridge and follow the diversion along the A85 Dundee Road to rejoin the A90 travelling northbound at M90 Junction 11.
Southbound Closure: Southbound traffic can exit the M90 at Junction 11 and follow the A85 to Queen’s Bridge where they will cross.
After the bridge traffic can turn left and follow the A989 until it reaches York Place, before turning left and following the A93 to Broxden Roundabout where they can rejoin the M90 southbound.
There will also be single lane closures on the A90 Barnhill Interchange underneath Friarton Bridge on Thursday January 30 and Wednesday February 5 as part of the works.
See www.trafficscotland.org.