Work on the £42m A14 widening project near Kettering is to begin in earnest in the new year, says the Highways Agency.
The project, which will eventually see a new lane added to the A14 in both directions between junctions 7 and 9 (A14/A509) in a bid to improve journey times.
The work carried out so far has largely been done overnight, and has involved tree pruning, construction of a central reserve and installation of traffic monitoring equipment.
The Highways Agency says the work in January will involve the construction of retaining walls, removing parts of the old carriageway and installing new drainage.
Barriers will be separating the workmen from traffic and there will be a temporary 50 mph speed limit along the length of the works, which the Highways Agency says will be enforced with average-speed cameras.
The scheme is expected to be completed some time between April 2015 and March 2016 and will cost approximately £42 million.
Traffic and speed restrictions were temporarily lifted during the Christmas and New Year period.
For information about the scheme, visit www.highways.gov.uk.