Diversions will be in place for six weeks after it was announced a busy Kettering route will close for major works.
The section of Northampton Road between Lake Avenue and the double roundabout will be shut from 4am on July 24 to 4am on September 4.
The continuous road closure is taking place for major work on the railway bridge as part of the electrification of the line between Kettering and Corby.
The work will strengthen the bridge – to allow more trains to use it – by repairing brickwork, installing tie bars and pattress plates and strengthening the spandrel wall.
Network Rail says it is doing the work during the school holidays to minimise disruption.
The official diversion will take motorists on to the A14 at Junction 8 and down the A43 Northern Bypass.
Road users should then travel down Rockingham Road on to Northfield Avenue.
The bridge will remain open to pedestrians.