Drivers face overnight closures and seven-mile diversions from today as work begins to install overhead sign gantries as part of the the £126 million M6 managed motorway scheme.
The legs for two gantries, spanning the width of the motorway, will be put in place on both carriageways on the Witton Viaduct.
This is between junction six at Spaghetti Junction and junction seven at Great Barr.
During the work, taking place tonight and tomorrow, the M6 will be reduced to one lane from 10.30pm to 6am in both directions.
The overhead sign structures will then be installed during two full overnight closures on Friday and Saturday. The Friday night closure will start from 10pm through to 8am the following morning.
The Saturday night closure may start as early as 8pm through to 8am the following morning, depending on how busy the motorway is.
A number of diversion routes, some spanning seven miles, will also be in place.
Highways Agency project manager Rob Edwards said: “This is a particularly exciting part of the scheme but not one without challenges. Installing gantries on an elevated section of motorway poses a number of issues.
“The road is eight metres above ground at this location, and we will be working at height more than five-and-a-half metres above the carriageway, so around 14 metres up in total.
“We have to consider wind loads at that height and have spent a lot of time analysing the elevated sections of road to make sure the structure can withstand the extra loads not only of the gantries but also of any additional pressure put on those gantries by the wind.”
Four more gantries will be installed on the Bromford Viaduct between junction five at Castle Bromwich and junction six, Spaghetti, on March 22 and 23.
Diversions will be in place throughout the closures.
Once completed, the £126.4m managed motorway scheme will cut congestion, make journey times more reliable and improve safety through the use of variable mandatory speed limits and by opening the hard shoulder as an extra running lane.
Mr Edwards added: “The scheme is progressing well and we remain on schedule to complete the work in spring 2014.
“We have had to juggle the programme around due to constraints of bad weather but nevertheless we are still on track, with nine of the 22 gantries installed so far.”
Drivers can follow the progress of the project on social networking site Twitter.